Portal is a rare example of a superb game included for free in a compilation (in this case the The Orange Box). The premise is relatively simple, but also unique: a gun that creates doors when it is shot. Two doors actually, and they are connected. As a result, players are able to place one door in an area that they can access and another in a portion of the board that they cannot. Then they go through the "portal" to access the previously inaccessible area. And that's just the beginning. By using their momentum, usually by placing the first door at the bottom of a pit, players can make themselves shoot out of the exit door at high speeds...and access even more far-flung areas. Like all the best games, this simple premise belies a surprising amount of gameplay depth.

The story is the usual -- and somewhat tired -- "psychotic computer trying to kill you." As the story develops, however, it is redeemed by the female computer's deadpan delivery of some legitimately funny lines. The closing song, which "she" also sings, is the funniest credits sequence ever. Playing Portal is a curious experience because the player is absolutely alone for the entire game, except for "her." There are traces and suggestions of previous human activity, though, which reinforce the feeling of loneliness. Especially when your only companion is the haunting yet monotonous voice of a completely untrustworthy supercomputer.

Portal is not to be missed. Any PC gamer will be delighted with it, and it will also appeal to novices because the gameplay is simple, progressive, and addictive. ~ Mark Hoogland, All Game Guide

Impressive, especially the physics-bending portal effects. ~ Mark Hoogland, All Game Guide

The eerie music and excellent voices add atmosphere. The closing song "Still Alive" is hilarious. ~ Mark Hoogland, All Game Guide

It's a short game, but a blast to play. ~ Mark Hoogland, All Game Guide

The additional challenge levels will keep some gamers coming back. ~ Mark Hoogland, All Game Guide