As long as the Dweller crisis remains unsettled, you should try Red Wizard. It uses the same sprites and tiles like Dweller. It is a nice little game with random dungeons. However, the dungeons are so random, once you climb up a level and go back down again, there will be a different environment. The goal is simple: Get from the lowest underground level up to the surface. Permadeath. Nasty curses and stuff. But I like it.
Pixel Dungeon was too hard first, then they made it playable, now there are so many editions out there that I have lost my interest in playing any of it.