Geometry Wars is one of the best success stories you're likely to hear: it started its life as a hidden bonus mini-game in Project Gotham Racing 2, and then went on to become a launch-title for Microsoft's fledgling Xbox Live Arcade platform on Xbox 360, quickly becoming one of the best-selling titles on the service. As if that wasn't enough, it's popularity led to a retail disc spinoff for both the Nintendo DS and Wii, further cementing the addictive shooter's status as a classic. Now the team at Bizarre are back with the game's first true sequel, the aptly named Geometry Wars 2.

The success of Geometry Wars was always its simplicity – a 2D, twin-stick shooter where you're essentially just shooting at colourful shapes in a small rectangular arena, striving only for the best multiplier you can to get the best score possible before your inevitable defeat. It's pretty much a textbook definition of old-school arcade gaming, and it was a formula that resonated with gamers and critics alike. So the obvious question is what can a sequel really hope to add, besides a fresh lick of paint? The answer, surprisingly, is a hell of a lot.

The first thing you will notice as soon as you fire up Geometry Wars 2 is that the game doesn't just have one play mode – there's SIX of them. The classic "Evolved” mode returns, as does a timed variant called Deadline where you've got unlimited lives but only three minutes to score as big as possible. The formula is not unchanged however, in fact there are two crucial differences, aside from a few new enemies: you don't lose your multiplier bonus when you die, but your weapons don't upgrade anymore. Where the average punter in the original game was unlikely to ever see a multiplier above 10x, in Geometry Wars 2 even a complete newbie can easily accrue 200x multipliers or even higher. The most this author ever attained was a 768x multiplier, and judging by my Friends Leaderboard, it's probably small change compared to what some people have managed.

So how on earth do the multipliers get so damn high? Well it's thanks to the other major change in Geometry Wars 2: the introduction of "geoms.” Geoms are tiny little green objects that drop whenever you kill an enemy, and picking them up increases your multiplier by one, and obviously they stack, and accumulate pretty quickly, especially in the later stage of a game. These little bonus boons only hang around for a few seconds though, so if you want to really see your score up in lights, you'll need to be pretty quick to pick them up. The result is a much more aggressive style of play, that encourages you to run *at* enemies as you shoot so you can snag their geoms and boost your score. It's a great shift in dynamic, and really makes the play style feel similar to the original but also quite different too.

Of course the real differences in play come from the other four game variants, each of which would be worth the price of admission on its own. Waves is similar to Evolved, except there's a wave of orange arrow-shaped enemies that spawn every few seconds, and that wave will wash across the screen vertically or horizontally until you destroy them. And if you don't destroy them, well, the waves just keep on coming, so if you don't keep a handle on things you'll be quickly overwhelmed by the unending assaults. You only have one life too, and with no bombs to get you out of a tight space, this can make for a pretty intense mode.

Then there's Pacifism, a hilarious mode where your ship cannot shoot at all, and the only way to take down enemies is to fly through small gates that look like a weight-lifter's dumbbell. Flying through the centre of the gate causes it to explode, taking out any foes in a small radius, but if you hit the dumbbell looking end pieces, it's game over. Ditto the enemies of course, and like Waves, it's a single-life, no bomb affair, and the blue enemies will be on your six the whole way, so you need to keep hitting the gates and thinning their numbers. Pacifism is fantastic fun, and the epic explosions as your gates take out dozens of enemies and constant near-misses as you somehow slide between huge groups of enemies make for some great moments.

But perhaps the most enjoyable new mode is called King. Like Pacifism, you can't shoot at all in most of the arena, except in a few circles that appear that is, and as soon as you fly in you can blaze away for a few seconds before the circle vanishes and you're on the run again. It starts easily enough, but as the number and variety of enemies increases things get pretty insane as you leapfrog from safe zone to safe zone. The final new mode is called Sequence, and like the name implies, it is a linear sequence of 20 missions that you need to beat in a single session. You've got your lives and bombs, and thankfully you can only lose one life per sequence before it simply ends that mission and moves on to the next. A Geometry Wars game that *can* end is a novel experience, but getting there is a whole different thing.

Honestly, these new game modes would be enough for most people to call this a great sequel, but Bizarre didn't stop there. Oh no, they decided that they would create a multiplayer mode too, one that lets you play through any of these new game types with up to four people on one Xbox 360, in versus or co-operative play. Versus isn't adversarial in the traditional death-match sense, it's really just a competition for best score and bragging rights. The inclusion of co-op is the real winner though, allowing you to all work together against your common enemy. Better yet, some of the modes – like King – let you literally team up, with one person controlling movement and the other on the guns. It's truly Geometry Wars like you've never played it before, and without a doubt some of the best fun local multiplayer gaming you'll ever have.

Sadly there's no Xbox Live multiplayer at all, but even a half second of lag for yourself or the enemies would render the game pretty much unplayable, so it's a disappointing but understandable absence. What the game does do with Live is populate a miniature Leaderboard snapshot for each of the game modes, comprised only of your friends list. This gives a constant source of inspiration to do better, and when you're playing, the high score displayed for you to beat isn't your own – it's the next person above you on your friends Leaderboard. It's a great touch and shows that the guys at Bizarre really understand the Xbox 360 framework, something that also shines through in the Achievements. These can involve dodging 8 waves without shooting or hitting 75 enemies with rebound shots, and this information pops up on the screen to let you know just how close you are to unlocking that Achievement.

Don't think you aren't getting the fresh lick of paint as well though, because Geometry Wars 2 looks really great. The colours are much more vibrant and neon than the original, and the explosion effects are much more detailed and mesmerising. They've also upped the bloom lighting, which makes everything seem a bit fuzzy and may hurt your eyes after a while, but it's also a nice reminder that you've been at it for an hour plus and maybe you should take a break! The soundtrack has been updated too – the classic Evolved track has been remixed, and each of the new modes boasts its own tune which is great. Of course you can always fire up a custom soundtrack, and Geometry Wars 2 is one of those games that will work beautifully or hilariously with almost any choice of music.