Actual Doomsday list (the pictured maindeck is a couple cards off and the sideboard is not close):
# Jimmy McCarthy
## Doomsday
MAINDECK
2 Island
1 Mystic Sanctuary
3 Polluted Delta
4 Scalding Tarn
4 Underground Sea
2 Volcanic Island
1 Ancestral Recall
1 Black Lotus
1 Brainstorm
1 Dack Fayden
1 Demonic Consultation
1 Demonic Tutor
1 Dig Through Time
2 Doomsday
1 Flusterstorm
4 Force of Will
1 Gitaxian Probe
1 Gush
1 Hurkyl's Recall
1 Lightning Bolt
1 Lotus Petal
1 Mental Misstep
1 Merchant Scroll
1 Mox Jet
1 Mox Ruby
1 Mox Sapphire
1 Mystical Tutor
1 Narset, Parter of Veils
1 Ponder
4 Preordain
3 Pyroblast
2 Sensei's Divining Top
1 Snapcaster Mage
2 Thassa's Oracle
1 Thoughtseize
1 Time Walk
1 Treasure Cruise
1 Vampiric Tutor
1 Yawgmoth's Will
Sideboard:
2 By Force
2 Fatal Push
3 Grafdigger's Cage
1 Hurkyl's Recall
1 Mountain
1 Pyroblast
2 Ravenous Trap
2 Shattering Spree
1 Toxic Deluge
1 Yixlid Jailer
The deck was really really powerful but I'm bad at magic now so I messed up a bunch. Should have easily won one of the matches I lost (it was on camera after the regular R3 or R4 match), probably could have won the others as well if I'd played better or mulliganed better.
List/board are 100% Sam Krohlow, his advice was basically to play like a control deck most of the time. Don't try to go off unless you're sure you got it (or, you know, you're about to die). I went off T2 maybe twice (mostly with DT -> Lotus -> DD -> free draw spell) because i had to, but otherwise most games didnt end until turn 6 or 7 at least.
Notable is the zero mana stack with top in play: gush/lotus/ancestral/oracle/petal (or sapphire): tap top, gush for lotus/top, lotus -> UUU, play top, tap draw, ancestral, U floating, 0 cards in deck, petal -> oracle. I won with that pile a couple times, including once on T2 facing lethal.
Personally i hated the shattering sprees in the board and wouldn't play them again. I'd try either an instant or another hurkyls or something. And I wouldnt mind having one more bomb maindeck, either another DD or maybe a tinker type effect or something, I had some games where I was clearly ahead but strugged to close out.
-Jimmy