Pixel Dungeon or the Shattered Pixel Dungeon fork is another fun one that takes a while. The only caveat is that, like most Nethack-like games, it's practically required to cheat and save snapshots of the game data to restore to to ever finish it.
@paulakreuzer You are both right. These games are great. My favourite FDroid game is still Apple Flinger. It has great graphics, physics and sounds but most importantly it still works on old shitty phones. 🤩 @fdroidorg