Has moments of greatness, but may be worth only renting.
A very basic explanation of the missions is that pretty much all of them last 2 to 5 minutes, about 60% are ultra-easy, about 30% are challenging enough to warrant multiple tries, and maybe up to 10% are really hard. Unfortunately there is a wayward mission here and there that has improperly explained mission objectives, and you'll find yourself failing repeatedly and never understanding why. Thankfully this is infrequent.
The story doesn't make any sense at all, whatsoever, I think they just made up a bunch of awful names and said "yeah, they're at war". It makes the otherwise decent quality voice work almost painful to listen to when the narrators seem overacting about a concept you have no idea about.
The biggest shame is the mech reconstructing - they give you all these options to work with but each option is 1. poorly described (for the most part), and 2. extremely expensive. So it's very difficult to know what it is you're buying and also not feasible to buy enough parts to really have fun with the mech building. I think I would enjoy this game a lot more if I had more rebuilding options opened to me, and it's not like they don't have the interface for it. You can make extensive changes and save favorite loadouts to stored schematics, which would be awesome if I could actually afford more than a few new parts.
Ultimately I gave this a 7.5 as a throwback to GameSpot's old review guidelines that stated a 9+ game should be played by everybody, an 8+ game should be played by anybody interested, and a 7+ game only would appeal to fans of the genre. For fans of hot mech on mech action, you'll probably love this one. Anyone else, definitely worth a rental because it IS fun, but not worth buying.