Lack of sound hurts it
The thing I did not like was how there was no sound in this. That being said, it was actually well designed for a game that was made in a fairly short amount of time. I was thinking it would be something about changing the colors but it wasn't. Who knew there was a game where the WASD and arrow keys had different functions? It took some getting used to, but I well, got used to it. It actually made some sound effects for itself with how the keyboard worked.
You have to kill and collect everything or else you can't advance. Once you get the hang of it, you should be able to pick off most enemies. They do not all come at the same time, so pace yourself for them. I liked the omission of the dark lines so you let the colors show how it works. While not much design, still fun to play.