One of the simple joys of reviewing handheld titles is that you should be able to play them everywhere, rather than doing all that stuff around the house you have to get finished (washing up, pleading with the bank, apologising to the girlfriend) before finally sitting down in front of your widescreen telly with a controller, notepad and pen at 1am. With a DS or PSP; the bus stop, the train station, the lunch break are all now a reviewer's best friends - why waste valuable time when you can finish off a couple of levels of this week's assignment? At least that's how it should be.

In the real world, handheld games can rarely be played on the move thanks to the average man's most beloved ally and the gamer's biggest foe, natural light. Granted the DS is generally just as guilty of this reflective crime as its Sony counterpart but, in hindsight, my attempts to play a PSP stealth shooter while on the move were optimistic at best. But it doesn't matter; just like it doesn't matter that you can't even consider turning it on unless you have all the curtains closed and are hiding under a blanket. You seriously won't care - this is a great game.

For newcomers to the series, including me (I'd heard the name but my knowledge extended little further), the Syphon Filter franchise is all about covert ops squad Precision Strike, led by gruff voiced hero Gabe Logan. Your job is to infiltrate the uninfiltrateable (look, I created a word) using the latest technology, stealth and the odd bullet or two, rescue somebody, pick up something or kill someone. To do this, you have a lot of people giving you mission updates through your ear and enough pairs of high tech goggles to fill an Olympic swimming pool. If you're thinking about Sam Fisher now (but not in THAT way) then you're not alone - Syphon Filter might be one of the forbearers of the third-person stealth shooter, but throughout Dark Mirror it's impossible to shake the feeling you're playing the next Splinter Cell, so ingrained in the collective gaming consciousness is this definitive franchise. This problem is certainly not helped by the lack of personality bestowed upon the main characters and the identikit henchmen you have to endlessly dispatch. About three missions in, though, you just start forgetting or caring about any of this and get down to business. Now this Dark Mirror is starting to shine.

The plot, something to do with terrorists taking something, is inconsequential and difficult to follow, and the game is so linear that moving unharmed from A to C via B doesn't require much more than common sense, mastery of your gadgets and being a good shot, but - for once - these are good things. Somehow Syphon Filter manages to make all these elements meld perfectly together, despite the visual and control limitations of its handheld home, creating a genuinely impressive, immersive experience. PSP shooters are few and far between for a reason and yet, once you master the ridiculously dull training missions, playing Dark Mirror becomes, quite literally, a doddle.

One standout sequence, set in a single large warehouse, sees you popping-up out from behind crates to take out bad guys, zooming across zip wires, removing laser mines (using your goggles to spot them, of course) and then finally stopping a massive detonation, all with a three-minute timer counting down in the bottom left corner. It's dramatic, exciting and a frankly nerve shattering sequence, but somehow I managed to pull it off on only my second attempt, so wonderfully executed is the game's design. Combat relies on defensive play (with odd daring flourishes), sneaking relies on advanced stealth tactics, and avoiding traps requires, well, avoiding traps. It's cold, simple and clinical, but you really won't hear anyone complaining because Syphon Filter works so very, very well.

With single-player and multiplayer game modes, it's an impressive package.

As you would expect, the odd glitch does pop up (why won't Gabe cling to cover when he is under fire?), the dumb AI makes killing a bit of a turkey shoot, and the locations are hardly a visual feast (although it's technically an impressive game) but, once more for luck, none of this matters. There are even a number of fully-armed multiplayer modes to master, meaning this fantastic game doesn't even have to finish after the main campaign ends. It is perhaps not as complete an online experience as SOCOM on the PSP, but the overall package is undeniably superior.

Providing you can find yourself a dark and secluded enough place to play it, Dark Mirror is the first great shooter for the PSP and, despite its lack of personality and unremarkable story, arguably one the most consistently enjoyable genre entries of the past year. Don't get me wrong, this is no Chaos Theory, but Syphon Filter does give its only handheld competition (in the shape of Splinter Cell Essentials) a quick, effective neck snap that I'm sure Mr Fisher would be proud of.