Basically, the game is setup to have an arena of play, followed by a cut-scene, and followed by another arena. The mode of play most of the time is FPS, but occasionally, you get a rail shooter. To mix things up, on occasion you get to pilot a jetpack (though incompetently), and a mech. These are a lot of fun, albeit they tend to break up the flow since they have completely different mechanics.
The story told in the cut scenes is entertaining enough, though not high art. The ending sucks, but seems in character for what's been going on in the series: the characters continually argue and bicker with each other while the protagonist hothead runs off and does something randomly crazy. It makes for a fun game, but a cliched story.
In any case, the game's got a few things that makes it fun even for a terrible FPS player like me:
- Plenty of NPC allies. You're almost never alone, and there's always fire support and if you don't rush off in front of your allies, someone will revive you even if you're killed. This is huge! It cuts down on the frustrations a lot, and you're never stuck for long.
- Plenty of variety in game play, and multiple paths to victory. In particular, even the stealth section is forgiving. You don't just die because you didn't stealth right. You get a chance to pick up an enemy's weapon and just blast your way through. Again, not frustrating.
- Lots of eye candy. The environments change a lot, and it's very different each time.
- Plenty of ammo reload locations. I think I ran out of ammo once. And you can always pick up the enemy's weapons.