Personally, I haven't played a shooter of any kind on a handheld that competes with this one. And that's not to say it's without flaws or even an all-time great game. But come on here... I like to play FPS games and now I can do it on the go. The small mission types with voice acting from characters we know from the Black Ops series. This is works for me and my portable gaming.
The multiplayer is a little disappointing if you're thinking the precision of a console Call of Duty. It's not there... but everything else is. The perks, killstreaks, weapons, and modes. You get a decent size experience for your pocket and I've had fun trying to earn 3 stars for all the missions. It's easy to get one star, challenging to get two stars, but three stars takes good runs to pull off. I like that kind of difficulty curve. Achievable but not a complete push-over.
It's a damn shame this isn't the best game ever, but it's not too shabby that it does do FPS better than any other handheld game... EVER.