Portal is a FPS platform puzzle game which focuses around the use of "portals" to reach the end of each level. A portal is essentially a wormhole that allows the player (and any object that can fit through it) to be instantly teleported to the portal's connected pair. To make things simpler for both the player and the developer, there are some rules on where and how portals can be placed. You can only have at most two portals open at any time, and portals can only be created on a flat surface: walls, floors, ceilings etc.

Diagram showing the Portal dynamic from the Portal Orientation Video no. 1

That's it. I know it sounds simple, but the use of portals as a gameplay mechanic opens up a plethora of possibilities for puzzles. You can use portals to cross large gaps or access areas out of reach, but that's just the tip of the iceberg.

There is very little story or background to the game. You play the role of Chell, a "test subject" for the Aperture Science Corporation. You start off in a small cell having just been awoken from "stasis". Guided, mocked and praised by the compound's super computer GLaDOS (Genetic Lifeform and Disk Operating System), you complete a series of "tests" all of which require the use of portals. The plot is slowly revealed by clues left by previous testers and the increasingly eccentric GLaDOS, whose occasional verbal slips reveal that all is not well within the walls of Aperture Science.

The first few tests are short and simple, designed to help the player understand how the portal mechanics work. The middle section of tests introduces the concept of controlling both portals (left click for blue, right click for orange) and "flinging". Flinging is the use of a subtle but important property of portals - conservation of momentum, or as GLaDOS explains: "Speedy thing goes in, speedy thing comes out". Using this property it's possible to reach areas high above the player and cross great distances. The last few levels put everything the player has learnt to use, sometimes in new ways, in order to finish the level.

The use of the portals is seamless and consistent through out the game. I encountered no weird physics or graphics bugs when playing - given the technical workings behind the portals that's an impressive achievement, and it's also paramount to the game's enjoyment. The level design is clean and simple and doesn't detract from the puzzles. The goal for each puzzle is usually clearly visible and the player is not left wondering where they have to go... although, of course, figuring out how to get there is all the fun.

There are however too many of the early "tutorial" levels. Yes the concept behind the game is hard to grasp at first, but do we really need our hand held for 16 levels? Levels 1 - 16 take about 30 minutes to complete. Depending on how quickly the player grasps the advanced portal concepts, the remainder of the game will only take a further 40-50 minutes - which makes the game short, really short. In replaying the story mode to refresh my memory when writing this review, it took me 58 mins from start to finish. Granted I knew how to solve all the puzzles but still it's only about 1.5 - 2 hours of game play all up for a new player.




Once the game is completed two bonus modes are unlocked, advanced and challenge. Advanced mode lets you replay six versions of existing maps. The maps have fewer places you can place portals, more water hazards etc making them a lot harder. Challenge mode lets you play the same six maps but with three types of challenges: use as few portals as possible, take as few steps as possible and finish the level as quick as possible. These two new modes give you another hour or so of game play and are a good challenge for those that thought the Original versions were easy.

Over all the game is fun, well executed, bug free, and challenging but due to its short length I'm giving it an 8/10.