[jsheard]

In general you can't copyright game mechanics, but trade dress laws provide a loophole around that. You can legally protect how a game is presented, and in some cases that's intrinsically tied to the game mechanics enough that you can't really get around it, which is how The Tetris Company has been able to effectively lock down the exclusive rights to the Tetris mechanics and successfully sued those who tried to make a Tetris clone without their approval.

[akudha]

If I made a scrabble app, is that not allowed? How come Wordfeud, words with friends etc are allowed?

[josephcsible]

But does the DMCA apply to trade dress?

[jsheard]

I am not a lawyer, but TTCs lawyers think it applies to their racket

https://itch.io/takedowns/1499978

[lupire]

TTC's lawyers' beliefs are not the issue. itch's cowardice is.