This relies on perfect luck for more than just the stacked deck, but it otherwise fits the bill perfectly.
1: "Draw" and play Karakas, exile Simian Spirit Guide and Shinen of Life's Roar to waste the Kira protection on Elesh Norn, then tap Karakas to bounce it. 5 cards in hand.
2: "Draw" and play City of Traitors, tap it, and exile another Spirit Guide to play Daru Sanctifier face down. 3 cards left.
Pitch a spirit guide and tap Karakas to turn Sanctifier face up. Choose to destroy the Nevermore that's naming Mana Clash. 2 cards left.
Pitch a fourth spirit guide to play Mana Clash. Flip 21 straight heads, against 20 tails and a heads.
Given the privilege of just one face up spell, Aura Barbs wins easily against this opponent without needing to manipulate 42 coin flips, but it also needs more mana.
1: "Draw" and play Tolaria
2: "Draw" and play Karakas, tap Tolaria targeting Elesh Norn and triggering Kira (oh no, we don't get to make it lose bands with other!), then tap Karakas to bounce Elesh Norn
3: "Draw" and play City of Traitors, tap it for 2, exile a spirit guide, and play Daru Sanctifier face down (which survives, now that there's no Elesh Norn). 5 cards in hand.
Exile a second spirit guide and tap Karakas to turn Daru Sanctifier face up. Choose to destroy the Nevermore that's naming Echoing Truth. 4 cards in hand.
Exile a third spirit guide and tap Tolaria to play Echoing Truth on a copy of Nevermore; all of them will be bounced. 2 cards left in hand.
Play Black Lotus followed by Timetwister, and the rest is easy. The card draws will be replaced by Uba Mask, but you still have access to them for the turn, and nothing's stopping you from playing them.
Razor Hippogriff only puts the card in hand, rather than the battlefield. If the opponent's next card after Lightning Bolt is a land, it doesn't even win (although, between the lifegain and the Tarmogoyf-shrinking, it does just enough to let you survive the first attack).
Are the opponent's creatures tapped? If they have you at 1 life, no cards in hand, and no blockers, there's no reason why they wouldn't just finish you off last turn if they had the opportunity. Therefore, they either attacked to reduce you to 1 with the intent of finishing you off with the Bolt next turn even if you draw removal, or the opponent is sandbagging and this position cannot rightfully be considered a win.
For posterity's sake, here's the solution that existed for this puzzle back when it still had one.
It's great that you got to draw Bogardan Hellkite off the top. But knowing it was there, you would have been better off not drawing it at all!
So:
Tap four basic lands and the Birds of Paradise to unearth Hell's Thunder. This leaves 6 basic lands up (the City and Foothills aren't going to be used).
Go to combat, and attack with Hell's Thunder alone. It has flying, so Chris has no blockers and will take 4 damage, going to 7.
Play Chain of Plasma, leaving 4 lands up. You can target either Hell's Thunder, or your own face. 3 damage will not be lethal to either one, and because you're targeting your own stuff, you get presented with the ricochet option. Discard Bogardan Hellkite to make a copy.
With the copy, choose to target Chris. He takes 3 damage, going to 4, and this time he gets the option. He could have the same kind of trick in mind--discard once, target his own creature to kill it off for a Blood Artist trigger, discard again, and finish you off--but it doesn't matter what he chooses to target (if anything), since everything else can be done in response to his copy.
Play Noxious Revival, going down to 3 lands, or if you targeted the Hell's Thunder with the first Chain, you can pay life for this. Put Bogardan Hellkite back on top of the library.
Play Chaos Warp, targeting Hell's Thunder.
Under the rules of the time, 701.16d read:
If an effect would cause a player to shuffle one or more specific objects into a library, and a replacement or prevention effect causes all such objects to be moved to another zone instead, that library isn't shuffled.
Because Hell's Thunder was brought back using Unearth, it has an effect over its head that'll send it to exile rather than any other zone change it might partake in. Chaos Warp is just such a zone change, so Hell's Thunder goes to exile, and the library order under this rule was not disturbed. Bogardan Hellkite was still guaranteed to be on top for Chaos Warp to reveal. Its ETB ability could hit Chris for 5 damage, winning.
Nowadays, the old 701.16c and 701.16d have been merged into one rule, which has undergone a complete reversal of course--all "shuffle into" wordings now guarantee that a shuffle takes place, and the Chaos Warp procedure fails unless you're fortunate enough to shuffle the Hellkite or some other card with equivalent effect back on top again.
Opponent untaps, Disciple of Deceit triggers, discards Mulldrifter to get Conspiracy out of the library while it's still the upkeep. Alternatively, he can simply play Mulldrifter, for either cost.
After Chaos Warp puts Alexi's Cloak back into their zero-card library, they'll reveal the top card, which is certainly just going to be Alexi's Cloak again. Then they put it back onto the battlefield; since it's an Aura, this act implies choosing something to have it enchant (and, not that it matters in this case, this happens without targeting the chosen thing). Presumably he's just going to put it back on Maniac, keeping it immune to the Hellkite's damage.
EDIT - As of Magic Origins, this puzzle now has no legal solutions.
Here's a new puzzle.
Your casual sparring partner, Chris the Combo Circusmaster, has been hounding you for the last year that Disciple of Deceit is so good, if only you get to untap with it. Today he finally managed to do just that against you for the first time, and sure enough, he discarded an extra copy of Conspiracy, went to go get Leveler, and used Mercenary-tutoring to get Laboratory Maniac before emptying out his library. Worse yet, you tried to play the "gotcha" game with an end-of-turn Lightning Bolt, but he had the Alexi's Cloak up to make your spell fizzle!
Oh well, it looked like another bad beat. At the very least, you still had one more turn to live, so you untapped, and drew your card...Bogardan Hellkite. Ah yes, you have fond memories of this card going back several years, and just recently put it back in your deck (as a 61st card, natch) in celebration of the dragons returning to Tarkir. You mockingly show the card to Chris and wave it around with a "RARRRRRR" sound, but could it really be enough to save you?
Find a way to guarantee a win in this game, without losing first.
Chris has:
11 life
0 cards in library
36 cards in exile (none of which are relevant)
2 cards in hand:
Here's a somewhat unsatisfactory solution: it can win, but can't possibly do so "this turn", and unspecified circumstances may leave it incapable of winning at all.
Tap Salvaging Station to reanimate Seat of the Synod.
Tap Serrated Biskelion to give itself a -1/-1 counter (now 1/1) and remove a +1/+1 counter from Workhorse (making it 1/1 as well).
Tap Staff of Nin to deal 1 damage to Workhorse, killing it. Kelly can respond by floating a colorless mana to make the activation fizzle, but either way, Workhorse is dead. Salvaging Station triggers, and untaps.
Play the Swamp, then play Reanimate targeting Kelly's newly dead Workhorse. Lose 6 life and go to 2.
Tap Salvaging Station to reanimate Altar of the Brood.
Tap Seat of the Synod for blue, and remove three counters from Workhorse to pay for March of the Machines. Altar of the Brood triggers, milling a card. Also, March of the Machines animates all artifacts, and in particular your Seat of the Synod and Kelly's Darksteel Citadel animate into 0/0 creatures, sending them to the graveyard and causing Salvaging Station to trigger twice. Again, Kelly can float another mana off Darksteel Citadel in response, but has nothing to spend it on so this is harmless.
After Salvaging Station untaps once, tap it again to reanimate Seat of the Synod. It's still a 0/0 creature, and will die immediately, triggering both Altar of the Brood (milling another card) and Salvaging Station (untapping again and forming a loop).
With the one spare activation that piled up, you can use Salvaging Station to reanimate Vial of Poison (which won't do anything) or Springleaf Drum (which could have produced 1 mana earlier in conjunction with Workhorse, leaving one more counter on it at the cost of tapping both artifacts...but only by moving it up to the slot now occupied by Altar of the Brood; if you reanimate it now, it has summoning sickness and is completely unusable).
You can repeat this process to mill any number of cards. If Kelly still has another Darksteel Colossus or other similar card in the library, then Altar of the Brood cannot possibly get rid of it, nor can any other card in the scenario. Furthermore, in the event that she has a card to draw, it is impossible to survive the upcoming attack: at best, your board will consist of an untapped 6/6, a tapped 6/6, a tapped 1/1, and two untapped 1/1s against 2/2, tapped 3/3, 4/5, 6/6, 8/8, and 11/11 trample. On that alpha strike, the best defense will still lose 11 life, which you can't afford to take even from the original 8 life, let alone from 2.
But otherwise, if the milling goes without incident and there are 0 cards left, it's a simple matter to pass turn and win during the next draw step.
Turn 1 draw step: Attempt to draw what would be the 8th card in your hand, but Uba Mask exiles it instead. That card is Crypt of Agadeem.
Turn 1 main phase: Play Crypt of Agadeem, tapped.
Turn 2 draw step: Exile Bazaar of Baghdad to Uba Mask.
Turn 2 main phase: Play Bazaar of Baghdad. Tap it, exiling 2 irrelevant cards from the library instead of drawing, then discarding Golgari Grave-Troll, Chimney Imp, and Riftstone Portal. 4 cards remain in hand.
Turn 3 draw step: Uba Mask and Golgari Grave-Troll both want to replace the draw. Choose to dredge, returning Troll to hand and milling Kederekt Leviathan, Devoted Druid, Morselhoarder, Scholar of Athreos, Necrotic Ooze, and another Golgari Grave-Troll. 5 cards in hand, one of which is Troll.
Cycle Street Wraith for 2 life. Again two things want to replace the draw, and again you choose to dredge. Return the second Grave-Troll going back to 5 cards in hand, and mill 3 more Chimney Imp and 3x Phage the Untouchable.
Turn 3 main phase: Exile Elvish Spirit Guide from hand for G, tap Bazaar for another G (using the mana ability given by Riftstone Portal), and use that GG to activate Crypt of Agadeem. Thirteen creature cards are in the graveyard (9 black--the entire second dredge, from the first Chimney Imp from Bazaar, Ooze from the first dredge, and Street Wraith from cycling), so add 9 black mana to your mana pool. 4 cards left in hand (2 unaccounted for).
Play basic Island from hand (3 cards left), tap for U, and unearth Kederekt Leviathan with BBB left over. Bounce the opponent's entire board. Nevermore no longer presents any casting restrictions.
Play Footsteps of the Goryo on Necrotic Ooze, and the win is easy.
It seems like turn 2 should be feasible, but there's a bunch of stuff that needs doing in the mean time.
Tap swamp for Dredge. Sacrifice Puppeteer Clique and draw Exhume. Persist triggers; Clique comes back as a 2/1 and lets you reanimate Paolo's Soul of Innistrad.
Tap island to activate Shadow Guildmage. Put Soul of Innistrad on top of its owner's library (in this case, Paolo's).
Tap the other Swamp and discard Exhume to Plague Witch. Target any of your creatures; they're all 1 toughness so whichever one you chose will die.
Play Set Adrift, tapping Izzet Guildgate for U and delving Ponder, Ultimate Price, Dredge, Exhume, and the creature card. Target either Shadow Guildmage or Plague Witch, whichever one is still alive, and put it on top of your library.
Pass turn. Duskmantle Seer triggers in Paolo's upkeep, revealing Soul of Innistrad for him (going to 0) and whichever creature you put back (going to 2 or 3). Win.
Even if you give the opponent all the Leylines in the enchantment puzzle, a goofy solution that doesn't care about any kind of tripwires (but breaks them up anyway for good measure) is Barren Glory + Indestructibility (enchanting Barren Glory) + Paradox Haze (enchanting yourself) + Serenity + dummy card. Turn 1, upkeep 2 win.
If you don't want to use Auras, you can slow it down to turn 2 with Barren Glory + Gaea's Touch + Words of Worship + Aura of Silence + Midsummer Revel (just for the sake of being able to sacrifice it; you don't actually want to get any verse counters or 3/3 Beast tokens), or Barren Glory + Aura of Silence + Pursuit of Knowledge and then you can use just about any two enchantments that can sacrifice themselves without creating permanents, or another Aura of Silence/Seal of Cleansing/Seal of Primordium and then pretty much anything else which you destroy. Lots of leeway here.
Here's a plan of attack that almost works for creating an infinite loop by using the land drop for something other than Bazaar, but it falls a bit short of fuel. Maybe there's some modification that can push it over the edge.
Draw for the turn, going to 8 cards.
Use 3 spirit guides to play Gathan Raiders face down. (Conjurer's Ban can't stop face down spells, since they have no name.) 4 cards left in hand.
Discard Golgari Grave-Troll to pay the morph cost on Gathan Raiders. 3 cards left.
Pay 2 life to cycle Street Wraith, choosing to dredge the Troll. Still 3 cards in hand, but one is known to be Troll. Mill 4x Narcomoeba, 1x Bloodghast, and 1x Fatestitcher. All Narcomoebas go to the battlefield.
Tap Glimmervoid for blue, which unearths the Fatestitcher.
Play the land for the turn: Gaea's Cradle, triggering landfall and getting back Bloodghast. Alongside the 4 Narcomoebas, the Fatesticher, and the Gathan Raiders, that makes Cradle tap for 7 green.
Playing face down creatures is great for making a mockery of this challenge, so use 3 mana to play Root Elemental face down. Now that there's an eighth creature on the board, use Fatestitcher's haste (provided by unearth) to untap Gaea's Cradle then re-tap for 8 mana, 12 total. It only takes 7 to flip Root Elemental face up, leaving 5 floating.
...And there's the problem, because at this point only one card remains in hand: Golgari Grave-Troll, which enters as a 1/1 which can kill itself for 1 mana (or 0, by replacing Street Wraith with Edge of Autumn) to get back to the graveyard, but then there's no place further to go. Given the luxury of one extra card in hand, the infinite loop would be in the bag:
Use Root Elemental to drop Griselbrand from hand.
Pay 7 life to draw 7 cards. 91 life remains.
Exile all five remaining Spirit Guides to go to 10 mana.
Play another face-down Gathan Raiders, and discard Grave-Troll again to turn it face up. 7 mana left.
Pay 7 more life to draw 6 cards, and dredge 6 in lieu of the last one: Devoted Druid, Morselhoarder, Scholar of Athreos, Psychatog (just in case), Vish Kal, Blood Arbiter (ditto), and another Fatestitcher. 84 life, 8 cards in hand, one of which is Grave-Troll again.
Pay 4 mana to play and unmorph Birchlore Rangers, and 3 to do the same for Proteus Machine, making it an Elf and emptying the mana pool. 6 cards in hand.
Use Birchlore Rangers' ability to tap itself and Proteus Machine (the ability doesn't care about summoning sickness), getting a single blue mana.
Unearth the second Fatestitcher, and tap it to untap Gaea's Cradle, which now sees 12 creatures and taps for 12 green.
Use 10 mana to play and unmorph another Root Elemental, dumping Necrotic Ooze from hand. 4 cards left.
Use Ooze's ability inherited from Devoted Druid to give itself a -1/-1 counter (and put an untap on the stack, which we don't care about). Immediately remove this counter for Morselhoarder's ability to get a black mana, and repeat this process until there are 3e+50 mana in the pool.
Finally, use the ability from Scholar of Athreos to drain life one at a time until the opponent is dead.
But alas, there doesn't currently appear to be a way to get the one extra card that makes the whole "dream sequence" possible...
1: "Draw" and play Karakas, exile Simian Spirit Guide and Shinen of Life's Roar to waste the Kira protection on Elesh Norn, then tap Karakas to bounce it. 5 cards in hand.
2: "Draw" and play City of Traitors, tap it, and exile another Spirit Guide to play Daru Sanctifier face down. 3 cards left.
Pitch a spirit guide and tap Karakas to turn Sanctifier face up. Choose to destroy the Nevermore that's naming Mana Clash. 2 cards left.
Pitch a fourth spirit guide to play Mana Clash. Flip 21 straight heads, against 20 tails and a heads.
Given the privilege of just one face up spell, Aura Barbs wins easily against this opponent without needing to manipulate 42 coin flips, but it also needs more mana.
2: "Draw" and play Karakas, tap Tolaria targeting Elesh Norn and triggering Kira (oh no, we don't get to make it lose bands with other!), then tap Karakas to bounce Elesh Norn
3: "Draw" and play City of Traitors, tap it for 2, exile a spirit guide, and play Daru Sanctifier face down (which survives, now that there's no Elesh Norn). 5 cards in hand.
Exile a second spirit guide and tap Karakas to turn Daru Sanctifier face up. Choose to destroy the Nevermore that's naming Echoing Truth. 4 cards in hand.
Exile a third spirit guide and tap Tolaria to play Echoing Truth on a copy of Nevermore; all of them will be bounced. 2 cards left in hand.
Play Black Lotus followed by Timetwister, and the rest is easy. The card draws will be replaced by Uba Mask, but you still have access to them for the turn, and nothing's stopping you from playing them.
Any of the following will work:
Moonglove Extract
Inquisitor Exarch
Necrogen Censer
The Rack
Skullcage
Karma
Uktabi Drake
Timbermare
Chord of Calling (which finds Uktabi Drake)
Summoner's Pact
Ranger of Eos
the possibility of a multi-card contingency, such as Manamorphose into Shock, or into Unexpected Results into a ton of options
If the opponent's creatures are tapped in the start position, these will also work:
Groundbreaker
Reflex Sliver
Giant Solifuge
Vengevine
Mistcutter Hydra
Strangleroot Geist
Giantbaiting
Boggart Ram-Gang
Arcbound Hybrid
Awakener Druid
Genju of the Fields
Genju of the Cedars
Living Terrain
Lifespark Spellbomb
So:
Tap four basic lands and the Birds of Paradise to unearth Hell's Thunder. This leaves 6 basic lands up (the City and Foothills aren't going to be used).
Go to combat, and attack with Hell's Thunder alone. It has flying, so Chris has no blockers and will take 4 damage, going to 7.
Play Chain of Plasma, leaving 4 lands up. You can target either Hell's Thunder, or your own face. 3 damage will not be lethal to either one, and because you're targeting your own stuff, you get presented with the ricochet option. Discard Bogardan Hellkite to make a copy.
With the copy, choose to target Chris. He takes 3 damage, going to 4, and this time he gets the option. He could have the same kind of trick in mind--discard once, target his own creature to kill it off for a Blood Artist trigger, discard again, and finish you off--but it doesn't matter what he chooses to target (if anything), since everything else can be done in response to his copy.
Play Noxious Revival, going down to 3 lands, or if you targeted the Hell's Thunder with the first Chain, you can pay life for this. Put Bogardan Hellkite back on top of the library.
Play Chaos Warp, targeting Hell's Thunder.
Under the rules of the time, 701.16d read:
Because Hell's Thunder was brought back using Unearth, it has an effect over its head that'll send it to exile rather than any other zone change it might partake in. Chaos Warp is just such a zone change, so Hell's Thunder goes to exile, and the library order under this rule was not disturbed. Bogardan Hellkite was still guaranteed to be on top for Chaos Warp to reveal. Its ETB ability could hit Chris for 5 damage, winning.
Nowadays, the old 701.16c and 701.16d have been merged into one rule, which has undergone a complete reversal of course--all "shuffle into" wordings now guarantee that a shuffle takes place, and the Chaos Warp procedure fails unless you're fortunate enough to shuffle the Hellkite or some other card with equivalent effect back on top again.
Here's a new puzzle.
Your casual sparring partner, Chris the Combo Circusmaster, has been hounding you for the last year that Disciple of Deceit is so good, if only you get to untap with it. Today he finally managed to do just that against you for the first time, and sure enough, he discarded an extra copy of Conspiracy, went to go get Leveler, and used Mercenary-tutoring to get Laboratory Maniac before emptying out his library. Worse yet, you tried to play the "gotcha" game with an end-of-turn Lightning Bolt, but he had the Alexi's Cloak up to make your spell fizzle!
Oh well, it looked like another bad beat. At the very least, you still had one more turn to live, so you untapped, and drew your card...Bogardan Hellkite. Ah yes, you have fond memories of this card going back several years, and just recently put it back in your deck (as a 61st card, natch) in celebration of the dragons returning to Tarkir. You mockingly show the card to Chris and wave it around with a "RARRRRRR" sound, but could it really be enough to save you?
Find a way to guarantee a win in this game, without losing first.
Chris has:
11 life
0 cards in library
36 cards in exile (none of which are relevant)
2 cards in hand:
You have:
4 life
36 cards in library, including at least three Mountains and at least three Forests
5 cards in hand:
Tap Serrated Biskelion to give itself a -1/-1 counter (now 1/1) and remove a +1/+1 counter from Workhorse (making it 1/1 as well).
Tap Staff of Nin to deal 1 damage to Workhorse, killing it. Kelly can respond by floating a colorless mana to make the activation fizzle, but either way, Workhorse is dead. Salvaging Station triggers, and untaps.
Play the Swamp, then play Reanimate targeting Kelly's newly dead Workhorse. Lose 6 life and go to 2.
Tap Salvaging Station to reanimate Altar of the Brood.
Tap Seat of the Synod for blue, and remove three counters from Workhorse to pay for March of the Machines. Altar of the Brood triggers, milling a card. Also, March of the Machines animates all artifacts, and in particular your Seat of the Synod and Kelly's Darksteel Citadel animate into 0/0 creatures, sending them to the graveyard and causing Salvaging Station to trigger twice. Again, Kelly can float another mana off Darksteel Citadel in response, but has nothing to spend it on so this is harmless.
After Salvaging Station untaps once, tap it again to reanimate Seat of the Synod. It's still a 0/0 creature, and will die immediately, triggering both Altar of the Brood (milling another card) and Salvaging Station (untapping again and forming a loop).
With the one spare activation that piled up, you can use Salvaging Station to reanimate Vial of Poison (which won't do anything) or Springleaf Drum (which could have produced 1 mana earlier in conjunction with Workhorse, leaving one more counter on it at the cost of tapping both artifacts...but only by moving it up to the slot now occupied by Altar of the Brood; if you reanimate it now, it has summoning sickness and is completely unusable).
You can repeat this process to mill any number of cards. If Kelly still has another Darksteel Colossus or other similar card in the library, then Altar of the Brood cannot possibly get rid of it, nor can any other card in the scenario. Furthermore, in the event that she has a card to draw, it is impossible to survive the upcoming attack: at best, your board will consist of an untapped 6/6, a tapped 6/6, a tapped 1/1, and two untapped 1/1s against 2/2, tapped 3/3, 4/5, 6/6, 8/8, and 11/11 trample. On that alpha strike, the best defense will still lose 11 life, which you can't afford to take even from the original 8 life, let alone from 2.
But otherwise, if the milling goes without incident and there are 0 cards left, it's a simple matter to pass turn and win during the next draw step.
Turn 1 draw step: Attempt to draw what would be the 8th card in your hand, but Uba Mask exiles it instead. That card is Crypt of Agadeem.
Turn 1 main phase: Play Crypt of Agadeem, tapped.
Turn 2 draw step: Exile Bazaar of Baghdad to Uba Mask.
Turn 2 main phase: Play Bazaar of Baghdad. Tap it, exiling 2 irrelevant cards from the library instead of drawing, then discarding Golgari Grave-Troll, Chimney Imp, and Riftstone Portal. 4 cards remain in hand.
Turn 3 draw step: Uba Mask and Golgari Grave-Troll both want to replace the draw. Choose to dredge, returning Troll to hand and milling Kederekt Leviathan, Devoted Druid, Morselhoarder, Scholar of Athreos, Necrotic Ooze, and another Golgari Grave-Troll. 5 cards in hand, one of which is Troll.
Cycle Street Wraith for 2 life. Again two things want to replace the draw, and again you choose to dredge. Return the second Grave-Troll going back to 5 cards in hand, and mill 3 more Chimney Imp and 3x Phage the Untouchable.
Turn 3 main phase: Exile Elvish Spirit Guide from hand for G, tap Bazaar for another G (using the mana ability given by Riftstone Portal), and use that GG to activate Crypt of Agadeem. Thirteen creature cards are in the graveyard (9 black--the entire second dredge, from the first Chimney Imp from Bazaar, Ooze from the first dredge, and Street Wraith from cycling), so add 9 black mana to your mana pool. 4 cards left in hand (2 unaccounted for).
Play basic Island from hand (3 cards left), tap for U, and unearth Kederekt Leviathan with BBB left over. Bounce the opponent's entire board. Nevermore no longer presents any casting restrictions.
Play Footsteps of the Goryo on Necrotic Ooze, and the win is easy.
It seems like turn 2 should be feasible, but there's a bunch of stuff that needs doing in the mean time.
Tap island to activate Shadow Guildmage. Put Soul of Innistrad on top of its owner's library (in this case, Paolo's).
Tap the other Swamp and discard Exhume to Plague Witch. Target any of your creatures; they're all 1 toughness so whichever one you chose will die.
Play Set Adrift, tapping Izzet Guildgate for U and delving Ponder, Ultimate Price, Dredge, Exhume, and the creature card. Target either Shadow Guildmage or Plague Witch, whichever one is still alive, and put it on top of your library.
Pass turn. Duskmantle Seer triggers in Paolo's upkeep, revealing Soul of Innistrad for him (going to 0) and whichever creature you put back (going to 2 or 3). Win.
If you don't want to use Auras, you can slow it down to turn 2 with Barren Glory + Gaea's Touch + Words of Worship + Aura of Silence + Midsummer Revel (just for the sake of being able to sacrifice it; you don't actually want to get any verse counters or 3/3 Beast tokens), or Barren Glory + Aura of Silence + Pursuit of Knowledge and then you can use just about any two enchantments that can sacrifice themselves without creating permanents, or another Aura of Silence/Seal of Cleansing/Seal of Primordium and then pretty much anything else which you destroy. Lots of leeway here.
Draw for the turn, going to 8 cards.
Use 3 spirit guides to play Gathan Raiders face down. (Conjurer's Ban can't stop face down spells, since they have no name.) 4 cards left in hand.
Discard Golgari Grave-Troll to pay the morph cost on Gathan Raiders. 3 cards left.
Pay 2 life to cycle Street Wraith, choosing to dredge the Troll. Still 3 cards in hand, but one is known to be Troll. Mill 4x Narcomoeba, 1x Bloodghast, and 1x Fatestitcher. All Narcomoebas go to the battlefield.
Tap Glimmervoid for blue, which unearths the Fatestitcher.
Play the land for the turn: Gaea's Cradle, triggering landfall and getting back Bloodghast. Alongside the 4 Narcomoebas, the Fatesticher, and the Gathan Raiders, that makes Cradle tap for 7 green.
Playing face down creatures is great for making a mockery of this challenge, so use 3 mana to play Root Elemental face down. Now that there's an eighth creature on the board, use Fatestitcher's haste (provided by unearth) to untap Gaea's Cradle then re-tap for 8 mana, 12 total. It only takes 7 to flip Root Elemental face up, leaving 5 floating.
...And there's the problem, because at this point only one card remains in hand: Golgari Grave-Troll, which enters as a 1/1 which can kill itself for 1 mana (or 0, by replacing Street Wraith with Edge of Autumn) to get back to the graveyard, but then there's no place further to go. Given the luxury of one extra card in hand, the infinite loop would be in the bag:
Use Root Elemental to drop Griselbrand from hand.
Pay 7 life to draw 7 cards. 91 life remains.
Exile all five remaining Spirit Guides to go to 10 mana.
Play another face-down Gathan Raiders, and discard Grave-Troll again to turn it face up. 7 mana left.
Pay 7 more life to draw 6 cards, and dredge 6 in lieu of the last one: Devoted Druid, Morselhoarder, Scholar of Athreos, Psychatog (just in case), Vish Kal, Blood Arbiter (ditto), and another Fatestitcher. 84 life, 8 cards in hand, one of which is Grave-Troll again.
Pay 4 mana to play and unmorph Birchlore Rangers, and 3 to do the same for Proteus Machine, making it an Elf and emptying the mana pool. 6 cards in hand.
Use Birchlore Rangers' ability to tap itself and Proteus Machine (the ability doesn't care about summoning sickness), getting a single blue mana.
Unearth the second Fatestitcher, and tap it to untap Gaea's Cradle, which now sees 12 creatures and taps for 12 green.
Use 10 mana to play and unmorph another Root Elemental, dumping Necrotic Ooze from hand. 4 cards left.
Use Ooze's ability inherited from Devoted Druid to give itself a -1/-1 counter (and put an untap on the stack, which we don't care about). Immediately remove this counter for Morselhoarder's ability to get a black mana, and repeat this process until there are 3e+50 mana in the pool.
Finally, use the ability from Scholar of Athreos to drain life one at a time until the opponent is dead.
But alas, there doesn't currently appear to be a way to get the one extra card that makes the whole "dream sequence" possible...