The atmosphere of this one is gorgeous, but it's also got some great gameplay too, and I would happily play more of it.
Pretty much the only gripes I had have already been raised on here by a few others, so I'll just mention what I liked. I LOVE opening the canopy. Even with no purpose, it's a great touch. The bootup sequence, physical interface and all those little immersive touches are sublime.
I think some tanks & tracked vehicles would work really nicely as weaker enemies, perhaps beefing up the enemy mechs.