Very loosely based :P. But a Lego transformer that actually transforms is hard enough to do. The fact that yours looks so great in both robot and vehicle mode, and at minifig scale, is really incredible.
Oh yeah! Nice. I really like the robot mode here. It's very posable, and has a good feel to it - almost like it's from the movie. The vehicle mode is cool - it has that "Cybertron" feel to it. Or maybe futuristic military. I like the color scheme, and the tasteful use of Bionicle parts. Good build.