The first Halo was rated M despite it really being more T rated from what I have heard. I know the Super Smash Bros games should be rated E10+. Is a freaking fat man farting and Pikachu beating up Mewtwo deserving of a T rating?!
Yeah, the thing is, with Halo, while there was a lot of killing and blood, the blood wasn't very graphic, the violence wasn't over the top gory, like in God of War, there was no six whatsoever, no language, no drugs, no alcohol, nothing glorifying inappropriate behavior like GTA, and the sci-fi feel made it feel a little cartoony, not like spongebob cartoony, but like a this-doesn't-feel-like-real-life-violence kinda way