Oh this was a very interesting game idea. Well executed too!
I like the simplicity of the style, and very nice particle system.
One thing that could have made life easier with my tactic (only using sparks and trying to remember where the creepy dudes were standing) is if the particles would have been global, so that I could see how far I rotated. The mouse was very sensitive for me, so a setting could have helped too.
A sound when you get attacked would have been nice too!
Very cool entry, I like it!