Gridrunner Revolution

The second factor is ship types. The sun itself can be attacked; you have to pour a bucketload of fire into it to destroy it, and while it fattens and prepares to go supernova, it fires pulses of energy back at you. But once destroyed, it becomes a black hole - offensively inert but still super-massive and able to jimmy around with your ballistics - and drops a new ship schematic for you to use. Different ship types have different angles of fire; some shoot straight forward in great barrages, some shoot fore and aft, some specialise in diagonals, and so on. Once you've collected a handful, you can switch ship types on the fly simply by scrolling the mousewheel up and down, to choose one which best suits the situation.

The situation is never simply 'kill the enemy' - you score higher points for destroying baddies using more intricate and complex arcs of fire. Heaven knows how it judges one fire-pattern to be better than another, but it works. The right ship-type at the correct orientation firing at the right angle near a black hole can set up dizzying eddies of destruction; streams of fire that turn into complete loops, or double back on themselves in figure-of-eight patterns, or wazz around in the sort of delightful curlicues and treble-clefs you might see on Mozart's scratch-pad after a night on the laudanum. It's a mechanic that's compelling, at times exhilarating, and turns the game from a simple, if charming shoot-'em-up into something rather more inspired.

Stylistically, it's very retro, as much because it tips the hat to previous Llamasoft games as anything else. The spacey trance soundtrack, psychedelic visuals and fixation with barnyard animals make it unmistakably a Jeff Minter game. But there are also some other cute touches, such as the Liberator from Blake's 7 that appears as a usable ship type. The game also changes the rules from time to time, which keeps things fresh. For instance, your weapon upgrades rely on collecting sheep, but occasional levels present black sheep, which don't want to be collected - you have to chase around the screen in a frenzy to grab them, which puts the thumbscrews on your baddie-mowing.

Graphically, it's a pleasing mix of old-school pixel art and modern Shader-Model 4 effects (if your graphics card supports DX10 effects, that is - it also features support for pre-NVIDIA 8-series and ATI X-series GPUs). At its quietest, it merely threatens to explode. At its most frenetic, it's a nuclear soup of pulsing colours, particle effects and alien soundscapes that thrill and engross in equal measure, with every level a perfect two-minute pop-song of rapidly intensifying effects. It's hard to walk away from once you get started.