While the perfect score of 40/40 awarded to Peace Walker by Japanese gaming magazine Famitsu may seem rather dubious given the in game advertising for said magazine, there is definitely some indication that it is in fact an incredible game. Because aside from the camera issues coming from the fact there is no easy way to adjust your view, there seems to be so much crammed into the UMD or download that it feels almost like you're playing a full-on home console Metal Gear Solid title.

Like Portable Ops before it, Peace Walker sees you in Naked Snake/Big Bosses' boots as he and the rest of the Army without Borders are hired by the awesomely metal handed Ramón Gálvez Mena (seriously, one of his hands is metal, painted red and he has a cigarette lighter in one of his 'fingers') to investigate why a military force with advanced weaponry has established a presence in Costa Rica.

It's November 1974 and Mena is a professor, with obligatory shady background and even shadier motives, of peace studies and he's been looking after a little girl called Paz (meaning 'peace') who has been abused by someone and she wants the army out of there to restore peace to Costa Rica and... well you can see this has already got pretty damn confusing in typical Metal Gear Style. Throw in a strange recording that seems to indicate that The Boss is still alive, even after Snake killed her in MGS 3, and you've got all the plot set up you and Snake need to go on another sneaking mission.

After the lengthy introduction to the plot and the tutorial, which is essential because there are a lot of ways of sneaking about and rendering enemies unconscious or dead, you're eventually let loose on the jungles of Costa Rica and your first mission is to retrieve some intel from the invading soldiers. Like MGS 3 and Portable Ops, levels are divided up into sections, sometimes there are soldiers to sneak past, sometimes there aren't and your camo index will tell you how well you're hidden. Making noise alerts guards and this can lead to some tense moments when you're only slightly nudging on the analogue nub to crouch walk past them hoping that they won't turn around and see you. If the soldiers do they go on alert and then you begin the biggest battle within the game - the fight with the camera.

I played it with the set up so that the camera controls were on the direction buttons. This lead to a lot of stopping, hiding behind whatever cover was available and scanning the area ahead. Pressing the R button centres the camera on where Snake is looking but when it all kicks off and the soldiers come looking ready to shoot you in the face it turns into a strange mix of trying to run away without actually knowing where you're running to. You could be running straight into another soldier while you've got the camera looking at who is chasing you and sometimes it's best just to try to leave the area and start that section again.

The lack of a second analogue nub really makes the game much more difficult than it should be. Perhaps you'd get used to it over time but initially it becomes frustrating that you can't easily see where everyone is, where they're going to and where they're coming from. The radar helps a bit, but only if you've got the surround indicator equipped and even then you'll really wish you could whirl the camera while you're walking about.

Anyway after infiltrating the base, noisily and by shooting everyone to death, wrong I know, the interrogation of the enemy radio operator began. It's an interactive cutscene requiring you to press several buttons at the right time. And this uncovers some more of the twisty plot. So I quit out and tried the co-op missions. I'm a bit selfish like that and didn't want to spoil the rest of the game before I really get to sit down and play it.

The co op mission I tried with several other 'Snakes' involved taking out a load of soldiers and their APC. It took us several attempts, it didn't help that one of us tried to take on the APC with a stun rod, so yeah he died pretty much instantly. You can revive your partners with some CPR but that gets pretty hectic when you're being shot at from all sides.

On the next try, this time armed with grenades and rocket launchers which were unlocked through completing levels in the single-player campaign, the soldiers were totally owned by explosions and a lot of gunfire. It's a good lark running around, popping out of cover and getting a few grenades off while other players distract the APC and its machine gun turret. But the real rewards come when you win and you're awarded experience points.

There are lots of points awarded for all your weapons based on what you used as well as more general points for how well you did. These can then be used at Mother Base to upgrade equipment, buy new weapons and so on.

In the single-player game you can also rescue other characters and use these guys in the side missions. Again, completing these will lead to more unlocks, more experience and more money to spend on everything else.

I barely scratched the surface of the immense amount of gaming within Peace Walker during my time with it, but so far it looks like it will be an essential purchase for PSP owners. Even if the camera is fiddly and as it's being released in the summer you're going to have to hide indoors because you won't be able to see anything when the sun shines on the screen. And as for 40/40? Give me a break, it's good but it's not that good.

Metal Gear Solid: Peace Walker is due for release on PSP on June 18.