12 cert, Valve/EA, Playstation 3, also Xbox, PC *****

Last week (according to Terminator mythology) was the week that Skynet computers started to turn against their human masters. That makes the release of Portal 2 pretty appropriate.

Like its predecessor, Portal 2 is a first-person puzzle game, pitting a human against a machine (the malevolent GLaDoS). Trapped once again in a crumbling giant maze, your individual tasks involve solving puzzles so you can pass through each room, while your mission is to shut down the main computer.

GLaDoS, speaking in a staccato, synthetic voice, is a passive-aggressive monster. Think Tony Soprano’s mother crossed with HAL from 2001, offering taunts and barbs as you work through the game.

The puzzles are mostly solved using your portal gun. You fire at one surface for an entrance, and another for an exit, forming (yep) a portal. This is handy for crossing rooms or transporting tools and objects. The physics are consistent and sound. So, for example, if you fall into a portal from a great distance, you’ll exit the next portal at greater speed.

You’re required to place objects on buttons, manipulate machines, and use lasers strategically. These tasks can be taxing and frustrating, but every one of them is logical and ultimately satisfying.

It’s a horrific premise, but Portal 2 is witty, and also somehow cute.

Stephen Merchant’s voice-over work is fabulous (he appears as a helpful robot drone), injecting some much-needed warmth to the artificial setting. As well as the single-player campaign, Portal 2 can also be played in a two-player co-operative mode, improving on its forbear.

This is a clever, captivating and sometimes hilarious sci-fi game, with compulsive gameplay. Here’s hoping I don’t have nightmares about GLaDos.