With the original Portal, Valve created a short but sweet game with a unique gameplay mechanic in which you create and walk through portals to solve puzzles. Not only was it new, but it was fun and challenging, and it was incredibly satisfying whenever you solved a tough puzzle. Flash forward to Portal 2, which has the exact same feeling of accomplishment and satisfying gameplay that made the first game such a big hit.

With Portal 2, all of the orginal Portal's gameplay elements are there, along with some new ones. You shoot portals at white spaces on walls and try to get to the door at the end of each test chamber. This time, Valve introduces new mechanics, such as the repulsion gel and the light bridges, to make the puzzles more challenging. These are very cleverly implemented, and a lot of the times they're combined in ways you'd never think of.

Of course, even with Portal's clever gameplay, it just wouldn't feel like a Portal sequel without the great writing. I'm happy to say that the fantastic writing that was in the first Portal is back, and in full force for Portal 2. Anytime you hear GlaDOS start talking, you know you're going to chuckle. Wether she's making fun of you, talking about testing, or reminiscing about old times, a laugh will escape your mouth.

Not only is GlaDOS back, but you get Wheatley and Cave Johnson, two new characters that add some nice variety to the writing. Wheatley, the bumbling personality core, is trying to help you escape Aperture Science. Of course, as with any video game, the plan doesn't go so well, and you end up testing with GlaDOS.

Cave Johnson, the founder and CEO of Aperture, is also great. All of his lines are pre-recorded, so there's no interaction between himself and other characters, but that doesn't make his lines any less hilarious. I'm not going to spoil anything in this review, but let's just say that you'll never look at lemons the same way again.

The graphics, even if running on the old Source engine, look great. They aren't going to blow your mind, but they definitely aren't going to hurt your eyes with ugliness either.

I never experienced any glitches with Portal 2, except the occasional physics screw up. Sometimes you'll be trying to place a turrent somewhere for an Achievement, and it just won't stand up the way you want it to. This can get pretty frustrating, though you don't have to deal with it if you don't care about Achievements/Trophies.

Portal 2 also introduces multiplayer, with it's co-op campaign. This is a welcome addition, as it adds different, more challenging puzzles in which you have to use four different portals to solve them. You start off with a tutorial teaching you the mechanics, then go to a hub world where you go to the different chambers. Think of it as a map screen, similar to Super Mario World, but in a Three-Dimensional space.

The puzzles in co-op are very challenging, but you have two brains to make up for it. If you want the best Portal 2 co-op experience, play with someone else who has never played before, both of you using mics. It's not as fun if one of you knows how to solve the puzzles, or if you aren't communicating with each other. Not only does that make figuring out what to do easier, but it makes the funny moments a lot funnier.

In closing, Portal 2 is a great game. It doesn't have a ton of replay value, and it gets a little boring at the beginning of the second act, but the good moments definitely out-weigh the bad. If you don't play Portal 2, you'll be missing out on one of the greatest games of this year.