Back in 2007, “Portal” became the breakout hit of Valve’s “Orange Box,” a collection of five games released in one package, because of its clever game play and witty dialogue from its memorable villain, the homicidal computer GLaDOS. Now, Valve has recaptured that magic with “Portal 2,” while simultaneously creating a longer game worthy of a stand-alone release.

The gamer plays as Chell, a test subject who awakens from stasis inside Aperture Science, a scientific research facility under the control of GLaDOS, the evil computer bent on revenge for her defeat at the end of the first game. The player must use the portal gun, which creates connected openings through which the gamer and objects can pass, challenging the players to cross rooms in unusual or tricky manners.

Portals help the player survive GLaDOS’ deadly challenges: puzzles created to test the portal gun. These puzzles require the player to use portals to move objects, reach high places  or manipulate the effects of momentum. This time around, however, there are some new, better toys to play with. The player must manipulate things like light bridges, tractor beams and laser beams with the portals. These new elements help to switch up the game play and add length. Learning how to use all these tools in conjunction with portals in order to effectively navigate the puzzles is a rewarding challenge.

Unlike many shooter games, “Portal 2” requires the player to think before every move — mistakes in timing or portal placement could mean death.  The game requires players to plan, thinking about a situation instead of just shooting to find a way out. Each puzzle tests the player’s intellect, but all are solvable through experimentation. Valve has perfected a system of giving the player clues, without outright giving the solution. Early puzzles get the player acquainted with how each tool works, from the lasers to the gravity lifts, before increasing the difficulty and adding more elements. Players new to “Portal” will find it easy to understand how the game works.

What is immediately evident after starting “Portal 2” is that this is a much larger world than the first “Portal.” While the graphics are nothing special, every nook and cranny is worth exploring. There are hidden small elements that expand their game’s world, such as posters on the walls, which help to tell the story of Aperture Science’s ultimate demise.

What set the original “Portal” apart was its incredibly humorous dialogue, and the strong story in “Portal 2” is no different. New characters, such as Wheatley, a robotic orb voiced by Stephan Merchant from the U.K. version of “The Office,” expand the world. Merchant, along with all of the voice actors in the game, obviously had fun with their roles. Every line of dialogue is worth listening to for its humor, to the point where the voices become just as entertaining as the puzzles themselves, considering GLaDOS and Wheatley’s antagonistic rapport. Expect to get plenty of laughs out of just listening to the game world.

Included in “Portal 2” is a special treat in the form of a cooperative game mode. In this mode, two players, each armed with their own portal gun, must work together to progress through the testing chambers. Valve makes clever use of the ability to have four portals instead of two, and builds on the game play conventions of the single-player mode. Working together to solve complex puzzles is a great addition to the game.

Ultimately, “Portal 2” is a game worthy of its predecessor’s legacy and praise. In a world filled with mindless first-person shooters, it’s a breath of fresh air to have a game that stresses brains over brawn.

4 out of 4 stars