This game is a rare gem. Not because of any technical wizardry, because honestly there were some fairly major glitches I ran into while playing (I had the PC version, YMMV on consoles). The reward in this game lies in a complex yet not convoluted storyline, absurd yet absolutely entertaining dialog, and compelling yet imperfect characters. Without going into the story too much, if you are a fan of guns, giant robots, and catsuits, you will be pretty happy with this game.
Full marks go to the boss designers. There were some very creative boss-level enemies to take on, ones which felt like they were work to overcome, but never so frustratingly difficult that you couldn't try a few different strategies and eventually hit upon the right one.
Oh, and exploding robots! The common enemies have numerous components which can all be surgically removed with copious amounts of ammo. The end result is incredibly satisfying, however after a while the common enemies start to seem, well, common.
But really, the fights were just interruptions between the cutscenes. The story is what makes this game worth investing the 12-15 hours required to really enjoy it. Crimes against humanity? Check. Love interest? Check. Clichéd banter between war buddies? Hells check. This game doesn't break any new ground, but executes in ways that make old tropes seem fresh enough to overlook. You do run into a few moments where any semblance of reality escapes out the window, but if you suspend disbelief for a while you're quickly returned to the more solid parts of the storyline.
The key to that storyline, though, is the voice acting. This game assembles (for the English version, anyways) a fabulous cast that really conveys the states of their characters effectively. There were some weak spots, but the main bunch deliver excellent performances throughout.
Since this game never really got the marketing push it deserved I have to figure it will end up in the bargain bin at some point. All in all, if you are looking for a simple, entertaining, and most of all *fun* game to pick up, this one will do you proud.