This was fun!
Looks really good, with a pleasant and distinctive color scheme. Controls smoothly. I like the various abilities (ice, rockets, health upgrade, etc.) and the way they gradually allow access to new areas.
The enemies are nice and aggressive. It would be more satisfying if there was more feedback when they died--e.g., an explosion (I think they're robots?).
Also, I did get a bit disoriented at times. A minimap would have been great.