Starship Troopers meets tower defense.
For the money Savage Moon offers a lot of game play. There are two modes. In the full game there are 12 levels which will take you aprx. 5-10 hours if you are just trying to complete the game. It will take longer if you want to do them and get a perfect score. A perfect score isn't easy in this game. The bugs will not always follow the same path and will often take a route less defended.
The second mode is Vengeance mode. In this mode your objective is too hold off the bugs as long as you can. The longer you hold on the higher your score.
My only gripe to this game is that I wish it had a few more types of bugs and that you could skip the intro sequence to the levels.
All in all this title is exactly what I expect from a download game. Lots of fun, good bang for the buck, and decent graphics and sound. A solid title 8.0