[quote=@Joshua Tamashii]
It's got things that look like giant robots. They're fighting. There's gunfire everywhere. It's a Giant Mecha Anime, no matter how I dice it.
[/quote]

I could probably get it... If there were more than one character with a giant machine... But their isn't... And the machine is an added gear that doesn't move o_o
So... I can't accept it being called a giant mecha anime... 
Gurren Lagann. Now THAT is a Giant Mecha Anime. One I love, but still. 
Accel World is definitely NOT a giant mecha anime. If anything it's a video game anime with some steampunk(I guess?) stuff thrown in. No different from .Hack or SAO or Log Horizon(I think that's the never... Never watched)