I could not figure out what was happening until I read a comment further down, the 'best' gun doesn't work on the last level! Is it supposed to be like this?
Every TD game needs speed-up/next wave button, otherwise it's just too slow. Good concept though, combining shooter with TD. Oh, and I get "Unknown error undefined" when trying to submit score.
Level 19 is SO frustrating to get perfect on. Dude! You just completed the Overachiever achievement in Hanna in a Choppa and won the Overachiever badge and 30 points!