PErfect Dark got an M rating because it showed some blood spatter.
besides, gore isn't part of TC:E's theme. Though it does show modern combat, the majority of the places that skirmishes take place are industrial. about the only people I can see hanging around the places that TC:E is going into are
a) employees of the area, which probably fled
b) criminals, probably as well armed as the mercenaries.
I think the stuff they have in the one map (gah! forgot it's name! it's the new one for .49) is good enough.
Titles rated T (Teen) have content that may be suitable for ages 13 and older. Titles in this category may contain violence, suggestive themes, crude humor, minimal blood, simulated gambling, and/or infrequent use of strong language.
Titles rated M (Mature) have content that may be suitable for persons ages 17 and older. Titles in this category may contain intense violence, blood and gore, sexual content and/or strong language.
to get your game rated M, all it takes is a little bit more violence and blood.
also, the "terrorist" side is made up mercenaries. at the current state of the game, thier goal is to destroy industrial targets, which would really hurt the economy of the target country. why the hell would you kil more people than you have to. rmember, every kill you make is another murder charge, therefore, ruthless slaughter != a good idea.