Nice song for a epic moment of a series or videogames, I don't think it's happy at all, neither suited for a battle theme or something like that, it makes me think of the violent and a little sad moment after a character has made a determinant decision, doing bad things for a greater good or sacrificing himself/herself for it.
Most important of all, this piece doesn't need any lyrics, even if it's greatly suited for them at it is, it inspires a lot without them.
In the beginning I had the idea it was more going to be an electro song than a rock song, but at 0:16 I got convinced it's a rock song. The main refrain is more happy than bad-ass, which is different from most rock songs, and I really like that! The kicks that come in at 0:08 are good and not too complicated. The part from 0:32 to 0:48 are missing some vocals though. It could just be me, but I think every rock song should have some vocals in it. They don't really need to be about something, but just some words that make sense.
Anyways, you did quiet well on this one!
Please contact me if you would like to use this in a project. We can discuss the details.