General idea: dungeon / labirynth mixed with a match3 game. As you walk through the labirynth, as long as it creates a proper match, you’ll be able to swap the tile you are on, with any of the neighbours. Matching tiles will then be cleared and new random tiles will be put in their place (no falling tiles). An algorithm that makes sure that walls / passages on neigbouring sides are the same, randomizes the geometry not only on the cleared tiles, but also on neighbouring tiles.

Not sure how far will I go with this idea

Now it’s time to get some sleep…