We always hear from developers that they've upped the scale, scope and all-round epic nature of their game for the sequel. So and so game has twice as many levels, another has bigger bosses, another includes some new moves. Ninja Gaiden Sigma 2 is a game that has more variety than you could ever imagine, a storyline that spans the globe, enemies so diverse you expect something new around every corner, combat so brutal you'll be wincing until the closing credits and a style that is effortlessly cool. Ninja Gaiden 2 was more bad ass than its predecessor in every conceivable way, and this PS3 exclusive refresh is even better... for the most part.

If you haven't been following the Ninja Gaiden series over the past few years you probably aren't prepared for how difficult Ninja Gaiden Sigma 2 is, even if it's definitely easier than the 360 original. It's still on a completely different level to current genre favourite God of War. To put Ninja Gaiden 2 into perspective, I was able to beat God of War and its sequel fairly comfortably on the default difficulty - on the easiest difficulty Ninja Gaiden 2 almost made me gnaw my fingers off at certain points. Newcomers will definitely appreciate Sigma 2's more forgiving gameplay, but unless you're 100 per cent focused don't expect to make it very far.

Although lead character Ryu Hayabusa gains quite a selection of weaponry as you move through the game, it's his block and dodge moves that are key to survival. You might be able to button mash your way through one or two enemies, but soon enough you'll be using health elixirs like no tomorrow and seeing the Game Over screen enough to have it burnt onto your retinas. Learn to use your block and when to counter attack and you'll be on your way.

Joining your melee weapons are a number of projectiles, ranging from your default shuriken to a gatling gun-style spear gun for use underwater. Most of these have a limited supply of ammo, with more available from fallen warriors you find on your adventure and at shops scattered around each level. Handily, Ryu automatically targets enemies when using a projectile weapon, although weapons like the bow and gun can be manually aimed if you want to hit a certain location on an enemy. One of the keys to the game is working out which weapons work best against each enemy type, so thankfully the d-pad offers a quick weapon-change, eliminating the need to go into the pause menu.

The new characters are great, but Rachel is a bit slow.

Your third means of attack comes from magic, or Ninpo as it's called in the game. Fire-filled icons below your health bar show how many Ninpo strikes you have at your disposal. Holding down Triangle and Circle initiates a monster slaying Ninpo attack and you have a few seconds to aim using the left analogue stick. As with your weapons, these powers can be upgraded, allowing you to dish out more damage. To begin with you're limited to a fire attack, but soon enough this will be joined by wind and fire bird assaults. Unless you're a true expert these special magic abilities will be essential during boss battles, so it's wise to stock up on replenishing items.

Brand new to Sigma 2 are three extra playable female characters. Rachel from Ninja Gaiden, Ayane from Dead or Alive and Momiji from DS game Ninja Gaiden Dragon Sword each offer a different gameplay experience during their brand new levels. Rachel is still as slow as she was in the original Sigma title on PS3, so is just as likely to divide opinion amongst fans, but the other two should go down quite well as their combat styles are fast and flowing like Ryu's. They each have brand new weapons to play with, too.

Enemies in Ninja Gaiden 2 come thick and fast and in large groups. You'll face warriors, giant lizard monsters, dogs, frenzied bats, gargoyles, metallic scorpion-like spinning nasties, werewolves, flying piranhas and more - in fact, that lot are just from the game's opening third. Your health bar in Ninja Gaiden 2 uses a replenishment system, meaning you don't need to use elixirs to get your energy back. When you beat a wave of enemies your health is re-filled, but any sustained damage (shown by red in your bar) is permanent unless you use a health elixir or blue essence. Fallen enemies release essences of various colours, with yellows acting as the in-game currency used to purchase new items and upgrade weapons, Reds replenish your magic, and blues heal semi-permanent damage.

You can play through special challenge missions with a friend online

You don't always want to absorb these essences for health though. By holding down the Triangle button Ryu draws them in, allowing him to unleash an Ultimate Technique move. These devastating moves destroy any enemies standing in your way and look spectacular to boot. The standard combat in the 360 version was extremely brutal, with limbs flying and blood spilling all over the place, but this PS3 game has been quite significantly toned down - something that is likely to anger and disappoint fans hoping this would be the ultimate version of the game. Limb and head dismemberment doesn't leave bloody stumps but instead a glowing purple patch. On 360 all the carnage remained in place too, with body parts lying strewn across the floor and blood smeared over walls. This just doesn't happen to the same extent here and the combat loses some of its edge as a result. Still, the new obliteration moves, triggered by pressing Triangle near to a damaged enemy, are pretty brutal.. It's essential you perform these finishing moves as enemies will keep going at you until they're dead - one set of enemies even commit suicide by blowing themselves up while on top of you.

In stills Ninja Gaiden Sigma 2 doesn't come close to showing its true beauty, although the reduction in gore has made the game less spectacular to see in motion. It doesn't have the same "WOW" factor of something like Killzone 2, but it's still a fine looking game when running at a pin-sharp 1080p resolution. The best is reserved for the bosses, which are immense. We're talking proper Shadow of the Colossus scale beasts here, each with numerous attack stages and techniques for taking them down. Just when you think you've seen it all you'll come face to face with another giant monstrosity that defies belief. As with the rest of the game, they're no push over either, with my PS3 controller coming dangerously close to being hurtled towards the TV screen on more than one occasion. Even better for PS3 owners is the fact that Sigma 2 includes a number of bosses not included in the original 360 game!

The Ninja Cinema mode lets you watch replays of your action in the game, but it's pretty basic. All you're able to do is watch what happened as if you're actually playing. Without the ability to change camera angles or slow down playback it feels like a mode that hasn't been fully fleshed out, which is a shame. Viewing some of the combat in glorious slow motion would have been great.

Completely new to the PS3 game is online cooperative play during a number of special challenge stages. It's a shame that there's no story mode to play through with a friend, but the inclusion of any multiplayer at all can only been seen as a good thing. It does make for a rather more chaotic experience, so be prepared for a screen full of carnage. Sadly there's no split-screen co-op, but you can play with an AI partner offline. With medals to go for and stages set across four difficulties there's plenty here to keep you playing once you're done with the campaign. You've also got online leaderboards, although given the game's hardcore following you're going to have to be pretty good to get anywhere near the top.

Graphically it's pin sharp, but lacking the gore of the 360 original.

Everything isn't perfect of course. The story is largely forgettable and simply serves to fill the gap between levels. Voice acting is pretty cheesy too, although the voices of the main baddies are typical '80s cartoon quality, which makes them sound pretty menacing and cool. Swimming is once again something I'd rather avoid if possible, with the underwater controls feeling a tad clumsy. Running on water is handled well, but if you get caught in a fight it's all too easy to miss an attack and fall in, resulting in some easy hits for your foes. Some complaints could also be levelled at the save points, which on occasion are a little too spread out and the frame rate drops from time to time during particularly action packed moments just as it did in the 360 game.

Playing Ninja Gaiden 2 is a very different experience to playing the majority of games. Whether it's for simply beating a wave of blood-thirsty bats or for finally slaying a boss you've been tearing your hair out over for more than an hour, the sense of reward and gratification is practically unrivalled. For every level you beat you feel like you're becoming a better gamer and that's a feeling that very few games can claim to give. This is action gaming at its very best, although with the toned down carnage during combat there's a nagging sense that Sigma 2's not quite the ultimate edition of the game it could have been.