Art and story (even if it was only in the game description) were good, the game was pretty slow until wave 9.
At first waves had little enemies which could be beat in ~1s, just for you to have to wait 5s for the next wave to start. Suddenly, at wave 9, there were a gazillion enemies and I died. I didn't get any further since I didn't know if there was a boss or if its infinite. I also noticed that I can shoot during the intermission, this isn't that useful but could be used to easily kill some enemies quickly when the wave starts.