Notes & Combos
DominiCanes's exodia deck, minus exodia
Like any good stun deck, your goal is to stop your opponent from doing anything. Except instead of beating them to death with pachy, you sit and wait until cauldron or final countdown kills them.
Don't mess up and fill your backboard before you play your win con, and don't be so unlucky that you don't draw one until it's too late.
If you want countdown to be your main win condition, consider adding gold sarcophagus, more copies of countdown or just more cards in general so you don't deck out.