game was pretty neat, got intense when the floor changed rapidly.
I really think that, before the floor changes, the tiles need to be a lot more visible than just outlines for the tiles, I had trouble at first noticing which tiles were going to drop and as a result I had to pay a lot more attention to where I was stepping instead of where I was shooting. It could also use a little more time before it changes too, which could be shortened as the difficulty gets tougher.
The pacing was kind of slow, the game is very simple to understand so I think the difficulty needs to ramp up really quickly. Hope you can go further with that floor mechanic, maybe adding different floor tiles that you can interact with?