In Judge's Tower, Each player has infinite mana, infinite life, and no starting hand (optional starting hand).

Every time you have priority, you must take all game actions possible before passing. This includes casting, activating abilities, and attacking and blocking.

Abilities can only be activated once each turn, and same goes for spells with the same name.

X is always .

When searching library, search the top 10 cards. When shuffling it, shuffle 10 and put them on bottom. If you would shuffle a card into library, instead put it on bottom.
To fail to find you must reveal the 10 cards.

I am considering playing with a chess clock. Passing priority would be represented by hitting the clock, and when you pass priority the opponent can call you on a rules violation, in which case you lose. Or lose to the clock.
Alternatively, you can have infinite time and only lose to mistakes.
This seems hard enough actually