Since the 1987 release of Metal Gear, the name of Solid Snake has been synonymous with great games. Over the years, the special agent in the skin-tight sneaking suit has become one of the greatest protagonists of the videogame industry, and his appearance in a game has become a trump card for the distributors. And now, to whet our appetites before Metal Gear Solid 4 makes its way onto PS3, we are being treated to an entirely new adventure featuring yet another Snake. And believe me, it's worth it, because Metal Gear Solid: Portable Ops is one of the most addictive and wholly entertaining games I've played for Sony's portable, carrying on the proud tradition of the series.

Portable Ops picks up the thread where Metal Gear Solid 3 left off. Six years have passed since Operation: Snake Eater and Naked Snake has been captured in a Russian military base in Colombia. Scattered about this base are the remnants of Snake's old FOX team, who have broken free of US government control and gone renegade. The entire base is led by a freaky guy named Gene, who intends to plunge the world into chaos by firing nuclear warheads at Russia. This doesn't sit too well with Snake, who takes up the call and leads a rebellion in the base, recruiting soldiers with moral issues to fight alongside him. The entire storyline is filled with ex-commandos, conspiracy theories, double agents, government medical projects gone haywire, schizophrenic girls with ESP and enough nuclear warheads to blow up the moon! It's complicated, it's Bond-esque and it's exactly as it should be!

The gameplay featured in Portable Ops has you sneaking up on defenceless guards, grabbing people from behind and hiding in cardboard boxes among other zesty things, enough to keep you entertained for the duration of the game. You control Snake with the analog stick and the camera with the d-pad, you aim and shoot with the shoulder buttons and the other controls are spread out across the face buttons. Suffice it to say, the controls work very well and are easy to learn. The shifting between first and third person perspectives when firing a weapon also works well, and the accuracy you attain is unsurpassed by any other game currently available for the PSP.

Sneaking around corners, hiding from enemies and launching at them when they least expect it is, of course, the cornerstone of the gameplay, and it is this part that you ought to be the most anxious about. Rest assured though, it works convincingly well. Dodging the prying eyes of enemies and grabbing them from behind becomes instinctive after a while, although the AI of your enemies often complicates matters. The guards dodge bullets, roll around corners and call for reinforcements the minute they spot you - most of the time, anyway. There are times when you can miss a guard completely with several shots, shoot his partner in the back and shatter the glass windows in front of him, without him taking the slightest interest in his surroundings. And it is possible to avoid the guards by simply crawling under a table, even with them watching you.

Should you be unlucky enough to trigger the alarm, you go through three phases of hiding; the frantic search for a safe spot, the tentative watchfulness and then the carefree cheerfulness of working your way out of your hiding place. These phases follow the three phases of the alarm - when you're first spotted, the closest guard notifies headquarters (if you don't manage to silence him first, that is). After a minute and a half, the search for you steps down until it comes to a halt at the end of the third phase - four and a half minutes after you were first spotted. Waiting this time out is often rather dull, so I heartily suggest that you don't let yourself be spotted - and if you do, have your shotgun ready.

In terms of visuals, Portable Ops packs one of the most detailed and atmospheric graphical engines yet seen on the PSP. Everything stands out clearly, the sprites are detailed and vivid, and even the weather effects look realistic. Not since King Kong have I been drawn so deeply into the world of a PSP game as I was here. Everything has a gritty and depressing tinge to it, which makes the otherwise far-fetched storyline all the more believable. The cut scenes are created in a unique and beautiful way too, consisting of original comic book art animated to look like an anime film. Several Metal Gear Solid veterans also provided excellent voice acting for these scenes, making them that much better. It was in all ways a wise decision not to let these scenes be created using the in-game engine, as this method gives the game a unique feel and works wonderfully.

The audio upholds the high standards of the rest of the game too; great voice actors set the mood in the intro, accompanied by a plethora of excellent audio effects. As you get into the game, you notice how much work has been put into making the audio moody and effective; from the silenced gunshots of your weapon of choice to the cataclysmic blast as you send off a rocket from a bazooka, everything is underlined with music fitting the tempo of the gameplay, changing to fit the on-screen action and remaining great listening throughout. The fact that the sound has been such a high priority has to do with how big a part it plays in the gameplay. You have a little radar in the upper right corner of the screen, which shows you where your enemies are by the sound of their footsteps. It also indicates whether you should be more careful to avoid an alarm, as it shows how much noise you make.

Throughout the game, you expand your team by hijacking random guards, scientists, soldiers and officers from around the base. You then convince them that their path leads to death, while yours is the road to salvation, and bingo, you've got yourself more mates for your team. You also encounter several characters that you can unlock by doing different things in the game. One needs you to alert him over the radio and then rescue him, while another simply needs you to defeat him. A lot of the unlockable characters are illogical to unlock though; I suggest that you grab a list off the Internet instead of just experimenting, as this makes the whole process a lot easier.

Once you think you've built up a strong team of psychotic misfits, you can choose to take the action online, battling other players across the world in real-time battles. However, these battles are purely action, where you attempt to explode each other using the nasty arsenal of weaponry you've attained in the single player campaign. This somewhat defeats the purpose of the game, which is focused on stealth, and when I realised that there is no stealth whatsoever involved in the online battles, I was more than a little disappointed. There are also a few other modes of play, one of which allows you to equip a team of soldiers and send them off into the ether, searching for battles to win. You select their tactics from a list, log off and hope they return safely. This allows for basically no playing of your own and only offers mild entertainment. The other features all of the game's bosses, collected in one long battle. This serves as great fun though, and valuable practice before you meet the antagonists in the campaign.

Metal Gear Solid: Portable Ops ranks amongst the finest games yet released on PSP. The storyline and single player campaign is really what it's all about though - expect nothing invigorating or original from the multiplayer mode and you'll be treated to a lightly pleasing diversion from the main attraction, a single player adventure with highly developed AI, excellent audio effects and music that adds atmosphere to the enterprise, wrapped in stunningly clear and clearly stunning visuals. Indeed, Portable Ops offers countless hours of entertaining espionage action and serves as a worthy addition to the Metal Gear franchise, as well one of the few must-have PSP titles currently out there.

Reviewed by Niels Jakob Kyhl Jørgensen for AceGamez (All Rights Reserved).