Nucleus

Nucleus is a 40-odd level campaign of biological warfare taking place within the human body itself: the digestive, circulatory and nervous systems, to be precise. You take control of the 'remote unit' - a jellyfish-cum-sperm shaped 'thing' that has the ability to shoot rapidly, drag cells about with a tractor beam, and accelerate rapidly ('squirt') to get out of danger.

At the centre of the game are the ever-present cells and the base proteins. Cells can be tractored, and 'squirted' into 'clumps' which then form a barrier against the viruses. They also yield protein when shot (as does pretty much everything) and as your reserves build you're able to fire off immensely powerful protein bombs - microscopic incendiaries that wipe out all viruses in any given area.

The bombs are also your only form of attack against the eponymous nuclei that pop up from time to time. These in-game 'bosses' are the source of the infection in the body and the main targets in the game, and they're also invulnerable to normal weapons - but they're not your only worry. Viruses multiply rapidly and mutate into more powerful enemies, to the point where the screen can easily be jam-packed with infection if you let things get out of hand. Collect power-up weaponry to keep you in the game, and learn to use those protein bombs wisely.

But there's more: Nucleus has its own 'ecosystem', its own series of relationships between its cellular inhabitants, and that's where the training mode comes in, giving you a crash course in how things work and introducing you to the different game objectives. Typically these revolve around exceeding a certain target score, killing off a nucleus or two, gathering power-ups, exterminating all viruses - or combinations thereof.

There's much to enjoy in this game if you persevere with it. Sure, the quality of the graphics varies wildly and the monotonous electronica from Rephlex's Bogdan Raczynski isn't brilliant, but a great deal of thought has gone into the gameplay and the environments. Each level has a knack of teaching you a new trick that you can apply to previous stages - which combined with the ranking system works well in getting you to improve your performance on previously conquered areas. It's also a game that makes you work hard to progress and while it's frequently insanely tough, that just seems to make unlocking new stages feel a lot more rewarding. Co-op two-player is a welcome way to spread the gaming burden, but that's your lot as far as multiplayer is concerned with only the usual online leaderboards exhibiting any Internet functionality.

It's been a long time since I've played a game where the odds are so hugely stacked against the player. It's difficult to avoid the sense that you're inevitably going to be overwhelmed by the sheer volume of virulent entities that crop up on-screen. Just small things could've made Nucleus a lot more user-friendly - being able to blast enemy fire for instance, would make a real impact on the game balance. Not giving the viruses momentary invulnerability while they're mutating and not allowing the nuclei to soak up protein and regain the power you've painstakingly bombed out of them would help hugely. Being able to 'squirt' faster or further (insert Peter North joke here) would make a huge difference in combat because right now it serves mostly as an aid for tractoring about large clumps of cells. The time limits imposed on many levels are frankly savage and on some stages you wonder why they're there in the first place. I could continue, but you get the picture.