Nice backgrounds, with an attractive dithering effect. The enemy models were very unusual and quite attractive. The main character looks decent enough, but as others remarked, blends in with the dark backgrounds.
A little more "game juice" (e.g., sound and visual effects when enemies are hit or destroyed) would have gone a long way.
The mechanic of phasing into another world when the timer expires is interesting, but it took me several tries to figure out that was what was happening. I think explaining that a little more clearly would have helped.