The essence of great design is making compromises without being compromised: Making pragmatic trade-offs without sacrificing creative vision or quality.

I'd love to be able to say that Metal Gear Solid: Peace Walker achieves this lofty goal, but ultimately it falls just short. But then, it wouldn't really be a Metal Gear game if it didn't suffer from one or two glaring flaws, would it? To its credit, though, Peace Walker is the best thing to come from Hideo Kojima's long-running series since Metal Gear Solid 3, despite a handful of compromising shortcomings.

Click the image above to check out all Metal Gear Solid: Peace Walker screens.

That Peace Walker would have to make some compromises is a given; it is a PSP game, after all. No slight intended to the system, but the PSP lacks either the horsepower or range of controls of the PlayStation 3, which played host to the most recent entry in the series. Yet despite taking a technological step backward, Peace Walker does an admirable job of reproducing both the spirit of MGS3 and the control mechanics of MGS4 to the furthest extent possible.

Certain Metal Gear standards have been streamlined or removed altogether in order to make the game play as smoothly as it can: Camouflage feels largely irrelevant, and it's no longer possible to crawl. For the most part, however, Peace Walker seems to have been designed with these limitations in mind -- in fact, the entire game feels very deliberate in its design. It was clearly intended to be a thoroughly portable experience above all else, and this is the source of its main appeal.

Far too often, portable iterations of console-based franchises are either grossly simplified in design or else attempt to do too much and ignore the realities of handheld gaming; the Metal Gear franchise is hardly innocent of these crimes. In Peace Walker, Kojima Productions has reduced Metal Gear to its essence -- sneaking, fighting, and watching -- and rebuilt it from the ground up to work on PSP. It carries over a few elements from its direct predecessor, Portable Ops (such as the base-building and mission structure), but by and large the developers have looked to other portable series (most overtly Capcom's Monster Hunter) for inspiration. The result is a game that offers up a quintessential Metal Gear experience, yet which feels perfectly at home on a handheld system.

At the heart of Peace Walker's design is the relationship between its single- and multiplayer components...or rather, the fact that it doesn't really have single- and multiplayer components. The entire game, be it the main story or the extra content, is divided into bite-sized missions that can be tackled solo or with up to three friends (with a handful of exceptions). Peace Walker can ostensibly be completed by a single person, though a sizable percentage of the extra missions (which greatly outnumber the story missions) are nearly impossible to complete alone. And even for the less daunting missions, you'll have a much easier time earning S-rankings with a friend or three in tow.

Click the image above to check out all Metal Gear Solid: Peace Walker screens.

This doesn't always work to the game's advantage, though, and herein lies one of its most significant failures. Like so many other games designed around co-op play, Peace Walker doesn't scale its difficulty according to the number of players. This is fine for the extra content, but it also makes for a handful of poorly-balanced story missions that can become infuriating sticking points for one person to tackle alone.

The bosses in particular suffer from this issue, and in fact Peace Walker's bosses are the lowest point of the game -- a real let-down in a series famous for its imaginative boss encounters. Don't expect to test your wits against clever super agents with flamboyant code-names this time around; Peace Walker's bosses are strictly military mechs and A.I. constructs, and they're all designed to be beaten by four people using sheer brute force. Worse still, the game's interface limitations severely hamper boss fights; Peace Walker's control schemes are a fair improvement over those available in Portable Ops, but they work best in slow, methodical stealth situations. In white-knuckle battles against towering mechs, they're often Snake's deadliest foe of all.