For this model, I used what I knew about Bionicles to make up for what I didn't know about mechs. The blades, torso frame, feet(mostly), and head are all made of Bionicle parts. A rather large improvement over my last mech.(Please excuse the photo glitch)
The theme here is not-quite symmetry. With his hands, you'll see that each side has a built-in gun and a blade (in one case also built in.) The legs escape this, and are identical. Making them different would look weird. The single cannon on his shoulder lights up.
I used Bionicle parts for the head and feet because I'm totally incompetent in those areas. Using them for just the feet probably saved me 30 minutes.