We finished the main storyline of Portal 2 a couple of nights ago, and I should say right now that there's absolutely nothing that I can say about it that isn't a major spoiler as far as I'm concerned. Even if I avoid the story entirely, there are so many elements that I really loved discovering entirely for myself - I especially enjoyed the Britishness of it, and the game has an odd sense of humour that rarely works in the genre due to the inconvenience of having to include the player in the script somewhere. I was pleased this time to get to the game before said game's legions of stupid fans on the Internet proceeded to ruin it - it was a new experience to be able to play through it without being able to recite the whole thing from collected fragments of text.

So don't read any of this if you haven't played it! (Sites I post to other than Livejournal don't have the benefit of cuts.)

I'm not sure how many people will agree with this, but the layout of Portal 2 reminded me strongly of the Abe games, with you exploring through multiple different sub-sections of a vague industrial building. The budget has been increased noticeably since the first, and throughout its much longer playing time it alternates between sets of puzzle rooms and action/obstacle sequences where you use the skills that you've picked up in the identifiable "levels". In places it feels rather like a Disneyland attraction as you're encouraged to barrel around routes through collapsing buildings, making plans up as you go and having to change routes very quickly as girders smash through walls or paths plummet into the abyss (though it does ruin the flow a bit if you accidentally follow them). But despite being so linear, the scripted sequences feel very natural - you're always forced on to one path, and yet you never feel boxed in, contributing to the game's sense of... hugeness. In others, you have to pick your way around precarious towers like in Prince of Persia and work your way up to the top.

While I'm on that subject, it took me much longer than you would think to realize that Portal was a puzzle/platformer - I had mentally classified it as a first-person shooter just for its perspective, despite it not having weapons. This time, I felt more strongly that it was a puzzle game, especially during the test chambers which were set up as individual puzzles - rather than just getting through them, I found that we were looking around each room first, working out the elements that we had and how they might be combined to be used, in a much more similar way to something like Rescue Rover than any other first-person game. New items get introduced on their own at first, and then as parts of much bigger puzzles where you have to combine many different elements, such as lasers, light bridges, and the dispenser pipes full of coloured "gel" that make the test chambers look like the aftermath of an episode of Fun House after you've finished with them.

As I mentioned, the sense of scale you get is incredible - in the first game, you had the thought that you were somewhere huge, but you never saw outside the enclosed maze of test chambers until near the end when you were taken off into claustrophobic tunnels. This time, in the middle of the game you're thrown into the depths of Aperture in an abandoned salt mine, and you discover just how massive it is - you're shown years upon years of buildings, with their contents somehow preserved in time. And when you discover that many of them are capable of being moved around like a huge Rubik's Cube, you start to feel even more small and at the mercy of the computer that's testing you.

I'm serious about not reading this, now

Since finishing it, I'm actually much more convinced of the tied-up GlaDOS metaphor than I used to be - as you can see in the best scene (best for having some of the funniest moments, the most distressing noise I've ever heard a computer make, and for the awful feeling you get just before the big twist), the AI housing is what drives personalities to insanity, not the AI itself. As you're forced to travel with Potato-GlaDOS later in the game she seems markedly less psychotic, and you're told that the computer gives its core a euphoric response to testing, encouraging it to abandon all rationality or care for its subjects and think of nothing but to blindly test, test, test (a feeling I can certainly sympathize with after doing my final CT2 playthrough).

The sense of cheerful wrongness in the game's sense of humour comes through in the history of Aperture, as well - in the first game, you were pretty much blind to what the company was like before everyone disappeared, but the story you pick up as you go through the various abandoned facilities gives you a view of them from the beginning. They were never... evil, exactly, in that they never intended harm - their problem was more just that they were completely mad. Their childlike fascination with "doing science" (as quoted by GlaDOS herself in the song that you've heard eight million times by now) without any apparent human understanding of anything they were doing comes through in ideas like the repulsion and propulsion gels being marketed as food additives, and the portal gun being overlooked as the greatest technological marvel than mankind has ever known and used instead as an aid to testing springy platforms. And the very last action that you do in the game is a wonderful moment, giving you an absolutely perfectly calculated amount of time to realize what you've just done.

We've still got the two-player puzzles to go through - I had wondered how the robots in the adverts were going to be incorporated, and nobody told me that there was actually an entirely separate game hiding in it. I've heard it mentioned that they invented the robots to give the two-player mode less of a sense of... mattering if you died - I'd love to hear the rest of the director's commentary, but as you only get it on the PC, I'm going to have to wait to see if the Playstation Network ever works again first. (I was reluctant about getting the PS3 version until I read that you effectively got the PC one free with it, and the controls really are nowhere near as unwieldy as you would rightly expect.)

One of the greatest things for now, though, is listening to the Barclay's Bank adverts, which Stephen Merchant voices in exactly the same way as he did Wheatley. Now, it's impossible not to think that you're being advised to switch to a fixed rate mortgage by a personality core who was specifically programmed to make really bad decisions.

Those videos are already full of comments like "They told me if I filled up my ISA I would die!". But at least they'll be funny for the next couple of days.