Mercury, eh? Funny stuff. It’s a metal, yet it’s liquid at room temperature. That means it can be made to flow where you want by tilting the surface it’s resting on, which sounds like a good idea for a puzzle game. Mercury Meltdown is the follow up to the original Archer Maclean’s Mercury, the game that introduced us to the joys of guiding a blob of liquid metal around various maze-like levels in order to reach the exit. As you would hope, this new game is not just a level pack; there have been tweaks to the gameplay and updates to the visual style too. The basic game involves guiding your mercurial blob around the level, splitting it up into smaller blobs, re-colouring it, and avoiding nasty mercury-eating creatures as the demands of the level dictate. You can also cause your blob to interact with various objects that are scattered throughout the levels. Doors, conveyor belts and other devices will help or hinder your progress. You should also be aware of your surroundings, as slippery floors will speed up your blob and sticky floors will slow it down. One of the biggest additions to the basic gameplay is the state of your mercury. Heaters and coolers will make your blob faster or slower and easier or harder to split up. You can even go through gates that will make your blob totally solid, making it possible to navigate rail paths or make jumps. You can also now play the game in two-player mode, and there are party games that you can unlock, including races, a golf-like game called shove, and the very intriguing rodeo where you have to keep your blob on a platform for as long as possible while a fan tries to blow you off. With over 160 levels and the promise of downloadable content to prolong the lifetime of the game, Mercury Meltdown will surely keep puzzle-playing PSP owners busy for quite some time.