Really neat idea for the theme! I would've liked if there was a progressbar or something so you can sync jumps with the next transition more easily.
The menu that pops up in the beginning is a little overwhelming when just starting out. Apart from that I had some trouble gaining height with the default rule-set but think this has a lot of potential!

There's a really interesting concept here, I'd like to see more done with it!

Great idea. Tried out some rule set and it took me a while how to figure out how not to get stocked into walls :-D

Hey, interesting approach, one issue I think I saw but not sure if that's intentional is that if the next block shows under you you wil not land on it. it's kind of not pausing when changing the blocks and collision fails?

Nice game! Really like the concept of the changing cave, got to 140 and gave up after falling.