It's a good stealth game with an exciting story that will keep you on the edge of your seat.
The story will draw you in right from the first two minutes of the game. It's told through comic-looking cutscenes. Nothing really moves, but it still looks great on the PSP.
Now, the bad stuff. First, its the controls. They are pretty complicated to learn and are not exactly your best tool when you find yourself in a tough firefight. There's a lock on feature and a handy radar but it still isn't enough from saving you sometimes. Second, the level designs. They are just too similar. Most of the maps have the same colors, similar-looking buildings, and rather boring features. Third, the variety of enemies. All enemies are put into one of about a dozen character types. All enemies in that type will look exactly like. And since there are usually only about three or less unit types on a single level, you'll find yourself sneaking past (or shooting at) the same guys over and over again. Fourth, the same dull mission objectives. You'll basically do the same things over and over again. Sure, one could say that it happens in almost every game, but Portable Ops somehow manages to openly remind you every time you do a mission.
Despite the bad things I said about this game, its still an awesome stealth-action game. If you particularly enjoy stealth or in a mood for a good story this game might be for you.