Atmospheric and fun to play. Nice music and environment. Controls are smooth, and the action stays fresh for a while.
I couldn't quite figure out if there was a theme--it made me think of a PlayStation-era Pac-Man. :)
The rectilinear enemies don't make an sound effect when you kill them (although the spherical ones do).
The Game Over screen appears for less than a second, and is gone in a flash--possibly because I was holding down the LMB, but in this game, the player holds down the LMB continuously.