The better you do the more stars you get (5 stars are max). Unlocking all the stars can be a nice goal after completing the game. There are 3 different difficulties. The 'normal' difficulty is very easy. Hard mode is only challenging in the begin. Insane difficulty is pretty easy in the begin, but it can get really hard to do every level at 5 stars in the end; there are insanely much robots jumping around and they hit hard. This makes the game easier over time (giving the illusion of getting better). And I don't think the game needs it. It's fun by it self and has replayability just for unlocking all the starts on all maps.
Style Platform Shooter
Release Date April 6, 2012
Developer Demiurge Studios
Publisher Ubisoft Entertainment