This is Keloid. It's not a movie. It's not a trailer. It's not even a short. It's just a "spec" project, a mock trailer made to let those involved flex their creative muscles and come up with their vision of a future where robots fight wars, and those robots look fantastic.
If you're wondering as to how the designs look so good, or even why in this post-Elysium-and-District-9 world they seem familiar, the concepts were done by some guys from WETA (who worked on Blomkamp's sci-fi flicks).
The spec itself was put together by Big Lazy Robot. Note: clip does not feature lazy robots.