Charles 'Chuck' Darwin had a big set of balls, that's for sure. Not only was he a great explorer and adventurer, but he also stuck two fingers up to old-fashioned beliefs with his controversial Theory of Evolution.

It's a cruel but perfect principle, and it works in gaming too. If you're not well adapted, you probably won't survive to help create the next generation. Far Cry Instincts was such a success that it's taken less than a year to spawn this expansion - but this isn't much of an 'evolution'. What you're getting here is eight story levels, eight multiplayer maps, three extra weapons and a new feral ability. It's not exactly a lot.

The story picks up a few months after the destruction of Jacutan. Jack Carver has hooked up with a femme fatale called Kate, and is reunited with Agent Doyle of the CIA during a gun-running mission. Rather foolishly, the trio comes into conflict with a tribe of bloodthirsty natives who somehow possess the same feral abilities as Jack.

While it's a fairly flimsy plot, much credit is due for the cut-scenes, all of which are viewed from the first person. They're really crisp and impressively directed. Stephen Dorff also does an excellent job with the role of Mr Carver. He's one of those rare videogame heroes that isn't actually a nice person. Kate is just as unscrupulous; she's the kind of lover who'd kill you in your sleep just to get her hands on your wallet.

In gameplay terms, almost everything is identical to Far Cry Instincts. It's still a little too easy to rely on the super-accurate auto-aiming. Likewise, the enemy AI isn't particularly threatening and you'll rarely feel like you're in serious danger of dying. Stealth tactics are always available, but, sadly, they rarely offer benefits over just storming in with guns blazing. We'd have loved to have seen at least one level where you had no weapons and had to depend on traps and feral abilities alone.

You begin the game with all the powers you attained on Jacutan; strength, agility, night vision and regeneration. This makes the first few levels really easy. Later on, however, the natives possess poison blowpipes that temporarily neutralise your powers. To make matters worse, these enemies also have super-agility and strength. They move and leap around just like the mutants from Far Cry Instincts' online Predator mode. Luckily, you can turn the tables and use the blowpipes against them, grounding them for a more straightforward kill. It's good to see the developer being a bit more inventive with the feral abilities.

There's one new one which does give the final levels a unique feel. By turning on your vision mode, you'll be able to see which wall surfaces and trees are now climbable. It's very exciting on the penultimate mission where you have to leap from rock face to rock face as you scale a vertigo-inducing mountain. There's one slight problem, though. Because climbing is automatic, you can end up hugging a wall just by accidentally brushing against it, which can be annoying.

Evolution's new projectile weapons also have useful effects on the environment. Molotov cocktails aren't that accurate, but they do set fire to big patches of long grass. Anyone caught in the blaze is incinerated in seconds. The big daddy of them all though, is the new pipe bomb weapon. This explosive has a remote detonator and is powerful enough to destroy sniper watchtowers. You won't find anything more satisfying than watching one of those structures come crashing down onto a platoon of mercenaries. It would have been nice if you could have destroyed other things too, though.

So what about the new levels? Well, the range of environments is easily the most impressive thing about Evolution. Although it's still set on a tropical island, you'll now have to venture through a pirate shanty town, an Ewok-style treetop village, a mountain range and an ancient temple. The locations look spectacular but also play quite differently from the original game. You're forced to climb terrifying heights and execute death-defying jumps on a regular basis.

A good effort has been made to make the levels as non-linear as possible. The second mission, in particular, is a masterpiece of design, and also one of the biggest maps we've ever seen in a game. In it you get to explore an entire archipelago, with three of the larger islands containing a challenging sub-mission. It's an absolutely beautiful tropical playground. Fans of the original PC game will recognise that this is the closest the console version has ever come to giving you a similar-sized environment. And thanks to the effective radar and compass system, you'll only get lost in paradise if you really want to.

It's possible to see for miles, and the binoculars let you zoom in on the tiniest details. At times you almost feel like you're on a sightseeing trip. Pop-up does occur on some of the later levels which slightly diminishes the realism, but it's nothing too serious.

Of course, if you think you can do better than the developer, Evolution's phenomenal map-maker will let you fulfil your creative ambitions. The system is so easy to use that you don't need instructions, and will be able to knock up a decent-looking level in around ten minutes. There's one new brush set based on an oil refinery, and there's a new forest template too. It's also nice that you can now build zip-lines where you couldn't before.

But before you delete all those old maps you made, it's worth noting that Far Cry Instincts maps can be imported into Evolution and actually remixed with some of the new items. Playing with this map editor is almost as much fun as the game itself.

Evolution is a very competent expansion, albeit one that's way too brief. Story mode can be finished in around six hours. It's also one of those add-ons where you rarely feel the developer has stretched itself creatively. The new ability and weapons are good, but lack any kind of wow factor. Despite this though, the Far Cry series' groundwork of solid playability and absolutely phenomenal graphics are still a huge draw. Evolution does everything right if you've an appetite for more of the same.

1. Slick and satisfying gameplay. And though it feels very similar to the previous game, the enormous maps make everything feel fresh.
2. Some of the best graphics on Xbox. With all-new islands to explore, the game looks better than it ever did. And those water effects! Wow!
3. Compelling level design. Now you can pick and choose which islands to explore first, making for a more free-roaming experience.

1. Story mode is too short. We know it's little more than an expansion but we would have liked to have seen more Carver action.
2. Not inventive enough with new features, and while the new Feral Climb is cool, we wish there had been more to play around with.

A playable enough expansion, but one that fails to improve on the original Far Cry Instincts.