Leaping from rooftop to rooftop, dropping onto unwitting enemies' shoulders for an instant kill, stealing valuable documents and then escaping the enemy fortress before anyone has even noticed you were there, this is what being a ninja is all about.

It may only be a handheld game, derived from last year's minor PS2 release of the same name, but when Shinobido gives you the chance to pull off great moments like the one above, it's hard not to be awed by how satisfying a gaming experience can be offered on the PSP. Sadly, the designers seem determined to limit such sublime sequences in favour of providing an endless array of alternate mission types, many of which stray far from the Tenchu-style thrills that Shinobido could have offered in spades.

Set in 16th century Japan, the normally peaceful lands of Utakata are now under threat once again, with enemies amassing for an all out war. The elite Asuka Ninja Clan would normally step in to protect the region, but they are nearly all pushing up daisies now, or more likely rare orchids. As the last remaining member, Goh, it's your job to battle the forces of evil throughout Utakata, gather some new allies along the way and wreak bloody revenge on those who wiped out your clan. To be fair, unless you have a penchant for Japanese history, the full plot of Shinobido is pretty incomprehensible and it's easier to skip through the reams of text that precede each mission and just get stuck into the action.

The best missions are where your ninja is tasked with wiping out everyone in town in the sneakiest way possible. This is where leaping between buildings, using your grappling hook to scale higher walls and pouncing on unsuspecting enemies comes into play and it's a genuinely thrilling system that works really well. Sadly, these sneaky tactics fall to the wayside as soon as you're spotted by a bad guy, and you're forced to resort to some old-fashioned swordplay. By old-fashioned I mean PSone level, where the camera (which is totally out of your control) swings wildly, enemies disappear through walls and taking on more than one opponent is tantamount to suicide. In fact, in an unintentional nod to Monty Python and the Holy Grail, the game sagely advises you: "When surrounded by enemies, run away." Outside of the smoothly executed stealth kill system, Shinobido's combat is never short of clunky and more often than not you're left to jab the attack button and put all your faith in the unpredictable target locking.

Despite this recurring gameplay blemish, the other mission types found in Tales of the Ninja predominately seem to revolve more around straight ahead fighting, making the game seem pretty blundering at points. From stealing items to protecting nobles and traversing dangerous landscapes (complete with leaping bears!), there are a wide variety of levels to master, but most of the time you will probably be yearning for the simpler stealth-based missions the game seems to have been intrinsically designed for.

Watch out for the bear!

Wisely, there are different paths through the story that you can choose to follow, offering a limited opportunity to avoid some of the more irksome challenges as you progress. Completists can also return to finish off the levels they missed first time around, or aim for better scores to be converted into experience points for upgrading their ninja army. Items also play a big part in Shinobido and using magical potions to boost your speed or even mechanical chicks (seriously) to distract guards adds an extra level of depth to the play, even if you don't have to rely too heavily on them to succeed. As you complete missions, more fighters are unlocked and each one's skills can be enhanced with new moves and talents. To be honest though, it's tempting to stick with just a couple of key ninjas and just build them up to near superhuman levels.

While the backgrounds and objects are all pretty blocky, the character design and overall presentation is remarkably good for a PSP title and it's easy to get sucked into this world of ninjas and odd samurai enemies, including stocky, armour clad foes armed with rocket launcher-esque weapons. The reasonable audio adds to the atmosphere too, with plenty of clanging swords and a welcome whistle sound whenever a stealth kill is available. Presentation is solid overall and the addition of ad hoc wireless battles for up to four players and downloadable content (such as maps) bolsters the reasonably-lengthed single-player campaign. The game has certainly been designed with the handheld format in mind too, as most of the levels can be competed in just a few short minutes or less - I even managed to finish one in less than 35 seconds, when my enemy stumbled off a ledge.

While Shinobido: Tales of the Ninja may be far from an essential purchase, thanks mainly to the dubious swordplay mechanics, it's enjoyable enough to sneak its way into a few handheld gamers' affections and, like Syphon Filter: Dark Mirror, proves there is plenty of life in the stealth genre on PSP.