Not bad.
I lost, like, 6 lives in 10 minutes to sudden landslides and sudden bullets (when I had to stay on a side). Warning signs could have been good - like for example a bullet's glow from off to the side - and (more visible) falling pebbles to telegraph landslides.
Also, doesn't really feel good when I get walled and I have to accept death (yeah I did have to restart a few times like this):
At least the game's short so it's kinda tolerable.
That's a nice-looking game though! My favorite thing is the stage theme, it's a jam.
P.S.: Someone should install a system to remote-control the air hatch :P