Rating issues
The characters in this game are all humanized insects. They look like insects, but often have a human stance, shoot weapons, work machines etc., like the movie Antz.
All the violence that is featured in this game, is unrealistic. You need to shoot insects and bosses multiple times before they die. When they do, their death animation is always the same. The smaller bugs explode in a green splash, leaving no visible trace of their existence. The bosses roll over and die, once defeated.
Other issues
The game features a few cut-scenes and bosses that feature mildly disturbing boss characters. However, this content does not raise the rating of this game, nor does it trigger the fear content descriptor.