I had never heard of Gachiakuta before. I was thinking it was just something you made up. Turns out I was half right. It's a real manga, but about to be an anime. No wonder I've never seen an opening for it! Anyway, this is amazing.
It's just nothing but pure action the whole way through. I don't know any characters obviously, but I can get the feel. It does seem like it was inspired by a lot of other anime. Maybe "Tengen Toppa Gurren Lagann"? That's just used to describe anything awesome.