SNK's Metal Slug games have always occupied an unusual place on the gaming landscape. While stuck defiantly in the past, they are certainly well loved, and older copies on the NeoGeo attract impressive bids when they do appear on eBay. They also have a reputation for excellence, but most gamers have never played them, or, have struggled to get to grips with their unique style.

Now they have come to the PS2, meaning a whole new audience has the chance to experience one of the most charming, trying series in the history of cult gaming. This anthology not only comes with the brand new Metal Slug 6, recently released in the PSP version of Anthology, but every main version of the game previously released, including Metal Slug X.

For those who have not had the pleasure of tackling a Metal Slug game, they are in essence 2D platformers which focus on intense shooting action over nimble leaping and pixel perfect landings. Undeniably, some of their genealogy is intertwined with that of another niche genre that attracts die-hard fans with deep pockets; namely the shmup.

Just like its more furious cousins, Metal Slug is all about dodging a sea of enemy bullets and unleashing your own torrent of lethal, garish firepower. The cult SNK series may not be quite as overwhelming as most shmups, but it nevertheless pushes its players to the extremes of their ability. Its bullet curtains may lack the density of those onscreen in the average shmup, but unlike piloting a tiny ship anywhere in the playing field, Metal Slug limits the player to the platforms dotted across the screen, upping the ante considerably.

But while one dot of a missile in Metal Slug may be as threatening as twenty in a shmup, it is far more manageable for the average gamer, and has tended to get a little more accessible as the series has gone on. The first Metal Slug for example, reproduced as faithfully here as the rest of the series on the PS2, concentrates on precise firing, reserving ammunition and methodical movement.

In contrast, the most recent version, which sets the machine gun as the basic weapon rather than the pistol, is more concerned with deft leaping, frenzied action, and a carefree attitude to your trigger finger. It also provides players with a range of characters to choose from, offering variation in strength and the devastating impact of your arsenal.

From beginning to end, each Metal Slug game on offer here is thrilling to play and hugely enjoyable. Compiling the complete range of games means that both hardcore and more casual tastes are catered for, but still we have not touched on the consistent genius that binds the series and gives the games their irresistible appeal.

Each, without exception, is filled with a huge amount of character, and an enticing sense of mischief and fun. Graphically, the Metal Slug games are now unique. Their heritage lies with the NeoGeo, a console with unrivalled sprite shifting abilities that really is the epitome of 2D gaming hardware. While other machines began their pursuit of the third dimension, the NeoGeo instead focused on the paper-thin world of 2D. Resultantly, it could produce wonderfully detailed backgrounds and sprites, with a depth most evident in the Metal Slug games.

Few games have as much character in their visuals

From the different ways otherwise identical enemies move across the screen, to the facial expressions, and hilariously silly, comically violent deaths, every moment is filled with detail. The combination of the swarming bullets, exploding scenery, and the life of every character on screen makes each Metal Slug a pixelated feast for the eyes. If the third dimension never existed, all games would have reached this point by now.

A two-player co-op mode also exists, which is certainly good fun in quick blasts, but as ever in a game of this intensity, to truly enjoy it and have the precision to proceed, you really need the clarity only a one-player game can offer.

Metal Slug Anthology is a worthy addition to any PS2 owner's game collection. It may be unusual, insistent on clinging to a long-gone gaming era, and incredibly hard at times, but by including every major Metal Slug game, is without doubt one of the finest platform shooter titles yet released.