If you’re looking for a cool little platformer to play around with, try out Cave Chaos from Nitrome. I’m still trying to figure out exactly what sort of creature your protagonist is, but I’m reasonably confident about calling it some sort of rodent. And for whatever reason, this particular rodent enjoys running around in caves which are constantly assembling — and disassembling — themselves.
What I really like about this game is its careful use of pacing, which surprisingly enough wasn’t really mentioned when I first saw this bugger being reviewed. Run too slowly, and the cave will fall away under your feet. Go too fast, however, and you may just find that the next platform suffers from a serious case of “doesn’t actually exist yet”. The physics are cool, yes, and the bats that are manually hauling in critical components of your platforming experience (namely, platforms) are pretty cool, but the fact that you’re trying so hard to stay in that “window of safety” while dodging enemies who are there to screw up your movement as opposed to raining death upon you directly … well, it’s refreshing.
Oh, and the graphics are nice. But go ahead and play it for whatever reason suits you. And please offer your theories on just what the hell that little furry thing actually is.