Portal 2

In evaluating Portal 2, it's easy to separate the game into its two modes - single-player and co-op - and, simply enough, both are great. Just in distinct ways.

Portal was a grand experiment, short and sweet, expertly exploring its sole puzzle gimmick in clever ways, while garnishing the narrative with Strangelove-ian black comedy. Portal 2's co-op mode inherits all of that, but feels similarly experimental and wild. The two-player campaign is brief, and, as with Portal, uses GLaDOS to enhance its strange, unique flavor; but with its impeccable puzzle/level design, and some ingenious innovations (I'd primarily cite holding Tab to see your teammate's perspective in real-time), is fantastically entertaining, while showing amazing potential for even more. It's a fair bet that Portal 3 will push the multiplayer envelope even further, using the groundwork that's been set here.

While Portal 2's co-op is evocative of its predecessor's spunk and spirit, the single-player campaign is an overall evolution of the first game's promise. I'll be honest -- in my short visits with Half Life and HL2, I was unimpressed by Valve's infamous in-game storytelling. Frankly, the story wasn't interesting enough, and the telling didn't feel like it was driving my experience. But Portal 2 takes Portal's antagonistic narration and expository ambience, and runs with it -- runs with it hard. I'm not completely on-board with the pacing so far - Stephen Merchant's delightful sidekickery is depressingly absent in the first few chapters, and I haven't even met JK Simmons yet - but the pre-existing rapport between GLaDOS and Chell really expands the story's potential, and GLaDOS exploits it, hilariously, at every turn. The witty voice-overs, the detailed setting, and the jarring in-game events conspire beautifully to really sell the story.

Of course, this is all not to mention the game's new mechanical gimmicks: vortices, light bridges, bouncy and hyperspeed paint, and perhaps more that I haven't encountered yet. Portal challenged the limits of its formula, and Portal 2 shows that there's always more to add.

The single-player is a near-perfection of the original game, and the co-op is a two-player experience that will invoke the same feelings you had playing Portal for the first time. Also, your co-op robot can high-five your partner robot. Or hug him. Or fight him! They're robots. Awesome.

Progress: Single-player: chapter 5, Co-op: finished