This was a fun time. Those are some extremely deadly spikes. Casually brushing against them instantly kills you!
A couple thoughts...
The enemies take a lot of shots but aren't very difficult. I ended up skipping them later on because they were annoying to fight after awhile. Maybe lowering the number of shots they take and alow lower the fire rate of the gun would work.
The controls were a little loose, but I liked flying around and boosting up the walls. I think you could have upped the speed of everything and it would have played a little better.