With five whole games crammed onto a single disc, it’s difficult to know where to start with The Orange Box.

The main game, if there is such a thing, is Half-Life 2: Episode 2, the second in a series of sequels to 2004’s excellent Half-Life 2.

As it happens, the original game is also included here in its entirety, along with last year’s Half-Life 2: Episode 1. Along for the ride are Portal, an entirely separate single-player adventure game, and Team Fortress 2, a multiplayer shooter that can be played online.

Half-Life 2: Episode 2 picks up directly after the end of Episode 1 and continues the story of scientist Gordon Freeman as he tries to save humanity from an alien force that holds Earth in its thrall. Granted, it’s not the most original of premises, but it’s the way that the narrative is executed that makes the Half-Life universe so compelling.

There are Orwellian overtones to the police-state setting, and the game evokes science-fiction heavyweights such as Ray Bradbury and HG Wells as well as more recent classics such as Starship Troopers.

Likewise, the game’s core mechanics are not hugely different to any number of similarly-themed sci-fi shooters, but it somehow feels more sophisticated and satisfying to play. As well as blasting your way through swathes of bad guys and monsters, for example, you’ll find yourself faced with several subtle puzzles and, in later stages, sections that involve vehicular exploration.

Unlike Episode 1, the new chapter feels less of a bite-sized chunk and more like a full game in its own right. It’ll take you a fair while to work your way through it, but the open ending clearly paves the way for the third and final part of the trilogy.

Though it's much shorter, Portal still deserves a full review. It’s an ingenious first-person puzzler that plonks you into a futuristic test centre with a special gun that can shoot a pair of portals (an ‘in’ portal and an ‘out’ one), allowing the character to bend space and pass through seemingly impossible environments. It’s a deceptively clever and occasionally mind-bending experience.

Team Fortress, meanwhile, offers the usual capture-the-flag and conquest-type online fare, though a combination of cool, cartoon-ish visuals and well-thought-out character classes makes it a cut above the average multiplayer title.

Suffice to say that if you haven’t already dipped your toe into the Half-Life 2 universe, then now is the perfect time to roll up your trouser leg and give it a go. This is a fantastic collection of games, and even if you have already paid for the previous two Half-Life 2 episodes separately, The Orange Box still wipes the floor with most ‘normal’ releases in terms of value and variety, not to mention imagination and inventiveness.

Vista compatible: Yes