Good game except for the yellow levels. Those were horrible and just generally not fun at all due to the extremely wonky way you have to fire your attack power.
Also this shouldn't be rated E. E means appropriate for everyone including the very smallest of children. "I cut the motherfucker head off" (actual quote from in-game), yet is rated E, lol.
Content-wise this is T at the very least. Language-wise it's M.