This article is going to discuss many aspects of Portal 2 in detail. There will most definitely be spoilers.

Valve's Portal 2, the long-awaited sequel to 2007's landmark Portal, was one of the most eagerly awaited games of the year. The Potato Sack Alternative Reality Game and the prospect of unlocking the game early stoked the fires of anticipation still further.

Just as with its predecessor, the reviews of the game have been uniformly spectacular, with the game currently standing at an impressive 95 percent on Metacritic. It is already being spoken of as a Game of the Year contender. But is this game really that good, or have reviewers been caught up in Valve's promotional fervor?

The first Portal game was a remarkable feat. It used the basic vocabulary of the first-person shooter, a genre familiar to any gamer, and gave it a unique (well, OK, not quite unique) twist. It was a first-person shooter in which we couldn't shoot. We could be shot at. Indeed, we would be shot at on a regular basis. But we couldn't shoot back.

All we could do was create portals—wormholes linking two parts of the level through which people and objects could walk, jump, or fall through. The Aperture Science Handheld Portal Device was no gun. It was simply a way of creating shortcuts from A to B. And what did we use our ASHPD for? We used it to solve puzzles in the name of science. Puzzles that would, as often or not, result in us being dissolved in acid, riddled with bullets, or vaporized by High Energy Pellets. We were in a first-person shooter environment, with first-person shooter controls and contrivances, and peril around every corner, but we couldn't shoot our way out: we had to think our way out. We had to think with portals.

And, dammit, the portals actually worked. It may seem a minor thing, but to me, the fact that you could actually look through them, use them to see the back of your head, use them to create a kind of hall-of-mirrors effect, fall for miles in a room only 20 feet high, was simply incredible. These were not dumb teleports of the kind we had in Quake. They were real, contiguous links between distant points in space, and they worked and felt exactly as they should.

That alone made Portal a fascinating game. A game worth playing, at least to try it out. The game invited experimentation. Though each puzzle clearly had a "right way" to solve it, the environment was malleable enough that many times we could devise our own solutions to the problems. I'm not going to pretend that this was an open-ended sandbox game or anything like that, but we could solve many of the problems in our own way. The game had this rich sense of discovery: we were not merely following the script, we could put our own unique stamp on the puzzles. The game was not just fascinating: it was deeply rewarding, too.

A journey into the darkest reaches of my psyche

But Valve didn't just create a game with a highly compelling core gameplay mechanic. It created a game that was rich in atmosphere. I realize that this is as much by accident as by design; the game was designed as little more than a tech demo, and the reason there isn't a huge back story, or any real exposition, or many different characters is as much due to budgetary and timing constraints as any deliberate effort on the part of developers. But the result is what matters, and the result had me gripped.

I can't play Portal at night. The game has this pervasive, soul-destroying feeling of solitude. The Aperture Science Enrichment Center is incomprehensibly enormous, and yet moving through it we meet not a single living thing. The test chambers are equipped with observation rooms—plainly there should be people up there—this should be a busy, bustling science lab. But they're all empty. The lights are all on, but there's literally no one at home. Even when we break out of test chambers, there's nothing. No scientists, no research assistants, no secretaries, no janitors, no maintenance men—not even any other test subjects.

The closest thing we get to companionship is GLaDOS, the murderous experimentalist forcing us to perform these tests. She calls it science, but she's no more a scientist than Josef Mengele. She voyeuristically watches over us, putting us deliberately in harm's way, and ultimately trying to kill us directly. There is no comfort to be had from GLaDOS. Comedic moments, sure. But all thoroughly tinged with evil.

This loneliness is further compounded by the Companion Cube. We're so desperately alone in the world that we form an emotional attachment to a metal box with hearts on it. We're willing to reach out even to an inanimate object in the vain hope that it will reciprocate our desires for interaction.

And finally, we have the Aperture Science Sentry Turrets. Oh, the turrets. Was a computerized killing machine ever so heartbreakingly melancholy? Their solitude is almost as profound as our own. "Are you still there?" they plaintively cry out into the void. With every turret I killed, I died a little more inside. We had to kill them—they were thoroughly lethal and had no qualms about killing us back—but I never wanted to kill them. Every dead turret was a gut-wrenching failure on my part. They were not bad; they were just victims of their own programming.

As I said, I couldn't play Portal at night. With the house silent, playing in the dark, just me and the game, it felt too desperate. I was not just the only person in the Enrichment Center—I felt like I was the only person on the planet. The feelings it provoked of existential despair were just too profound. I had to play it during the day, just to retain that connection to the outside world.