Love the art. Like the gameplay. Level design could definitely use more variety. Also, you might want to add that you can move in the direction where there is "void", so you need to be a bit more careful with what you press or you die. You can now sort of brute force it by just mashing buttons.
I also ran into the bug where you phase trough a wall, I think it happens if you have some "slowdown" glitch where the framerate drops due to reasons outside of your control. No idea if that helps in understanding why it happens.