Source PSPFanboy:

Syphon Filter hasn’t made a striking appearance on a console since, well, the first Syphon Filter came out on the PSOne back in 1999. Fans of the third-person shooter can breathe a sigh of relief then knowing that the newest addition to the franchise, Syphon Filter: Dark Mirror for the PSP, has made an equally large splash.

Excellent graphics, effective use of the PSP controls, and great online multiplayer mark Dark Mirror “the game to beat on the PSP” by IGN, and while 1UP has issues with the originality of the story (“The story…isn’t something to pay close attention to”), both they and GameSpot agree that the ability of the game to play well even without the help of a second analog stick is a blessing.

Gee; two great games and news of several landmark peripherals in the span of a week. Suddenly that feeling I had as a neglected PSP owner is feeling somewhat less soul-deadening.

IGN (9.3 / 10) – “Syphon Filter: Dark Mirror packs an uncommon amount of detail, variety and overall quality. It blends intense action sequences with stealth in a way no portable game has before, and it does so with style to spare.”
1UP (8.0 / 10) – “Better than any PSP shooter yet, Dark Mirror functions without a second analog stick. The extraordinary grace of the remaining controls is enough to almost forget how nice dual-stick control would be.”
GameSpot (8.8 / 10) – “With everything Dark Mirror has to offer, including its great controls, varied campaign, and high-caliber presentation, Syphon Filter is easy to recommend to anyone who likes action games.”