Undeniably one of the best PSP games available.
I'll start with the graphics. This is the best looking PSP game hands-down. At times, I forget I'm even playing on a PSP and not a 360. The cutscenes are shockingly realistic, and the game itself is almost equally beautiful.
Gameplay is almost too good, and incredibly addicting. I often replay levels just because they're so fun. Combat is a blast, and the variety of melee attacks and weaponry techniques makes the game all the more interesting. There is a vast variety of weapons, from the silent K-bar assault knife to the knock-you-on-your-butt USAS-12 shotgun. AI isn't as bad as the reviews say (for future reference, don't always believe everything the reviews tell you). Sure your opponents aren't the smartest guys out there, but they aren't "stupid and nonsensical", as the reviewer says.
The plot isn't "stupid and nonsensical" either. my guess is the reviewer learned the word "nonsensical" the day before and was dying to use it. The plot isn't as cut and dry as it seems at first. Its not your typical "spy saves the world" plot as you might suspect.
Acting is decent, and I have no complaints. The one thing I do have to complain about would be how seemingly infallible your opponents are. I understand that flak jackets protect you from bullets, but I've yet to discover the armor that takes 3 solid bursts from a TEK-9 automatic pistol and keeps its owner on his feet. Aside from that, great game!!!