very cool - I loved this little experience. Am I right in saying that there are just the 4 waves? The game seemed to stop after the 4th wave for me. Cool mechanics in the gatling gun, the missile launcher, and the planetary shield - I would have loved for each wave to last a bit longer and get a bit more crazy. I had the money but didn't actually get to use the shield at all. The explosions also sounded very 'spacey' - loved those. This was fun - great job.