You've heard of Portal 2, but are you ready to play Portal 2? Do you need help determining which part of the game to play first? Want to know how to find the game's coolest hidden items?
The answers to that and much more are below (some of them hidden behind links, to protect unspoiled eyes.)
Should I play Portal 2? Yes. It is very good.
Console version or computer version, which should I play? The computer version is supposed to have mod support, so if you really like Portal games, I'd nudge you in that direction. I played it on Xbox 360, however, and had a wonderful time. The PlayStation 3 version is also an excellent option, especially since buying it gets you the PC and Mac editions for free.
Do I need to have played the first game? No, but it would be nice if you did. It's true that playing the first game will diminish some of Portal 2's magic. The series' ingenious puzzle design can only be brand-new once. But a quick five-hour zip through the first game will give you a good handle on who the few main characters of this series are and why a certain someone feels the way they do in Portal 2. The simpler gameplay of the first will also help train your brain for the tougher portal manipulations of the sequel. (You can find the first one cheap for PC or consoles; the downloadable Portal: Still Alive on Xbox 360 includes bonus challenges.)
The game has a singleplayer campaign and a co-op campaign. Which should I play first? While you are technically able to play either campaign first - without fear of one spoiling the other - I recommend you start with the co-op campaign. The co-op campaign doesn't have much story to it, but the little it contains will do more to inform the story of the solo campaign than vice versa. The drawback to playing co-op first is that you're going into the deepest end of the Portal 2. The game's toughest puzzles are in co-op.
If I play co-op, who should I play it with? I strongly suggest you play with someone else who is new to the game. Figuring out the puzzles together is more satisfying than being led around (or having to do the leading). That said, on my second play-through of some of the co-op campaign's chapters, I struggled to remember how to solve some of the rooms. The game is tough enough that you'll forget some of its puzzle solutions. So, if you're replaying, I hope you have a short memory.
How long is co-op going to take? And when can I take a break? The co-op campaign took me about seven hours to complete, but its five-chapter structure encourages players to commit to about one to two hours per session. Once you hit a chapter ending, you might as well take a break. Thankfully, you can actually take a break mid-chapter as well. The game saves your progress after you to the elevator to the next challenge(s) in a chapter's eight or so sections. The game remembers the progress of each player and allows any paired players access to all the challenge areas that the more advanced player reaches. (The game also tracks each player's steps walked, hugs given and other silly stats, combining that data of each co-op pair to show how those numbers add up for the duo you're a part of at the moment.) Add this all up and it means you don't have to worry about playing through the co-op campaign all at once, nor with the same person all the way through.
But this game has a reputation already for being short? True. There's heated debate about whether the game's worth a full $109.95 on consoles ($89.95 on computers), but with the singleplayer campaign taking about nine hours for me to finish, and never hitting an unpleasant patch, I say there's plenty of value here. There's less value for people who want to be able to replay their games, though the game does reward repeat players with an option to activate developer's commentary.
Any hidden secrets? A few, including a hidden song and a reference to another Valve game. Here's how to get to them.
How's the new song? One of Portal's claims to fame was its end-credits song, "Still Alive" by Jonathan Coulton. There is a different song playing during Portal 2's end credits. (Listen here.) I didn't like it as much, but it's still pretty good.
Did they include a cake joke? This is a spoiler-free article, so I've put the answer here.
I'm stuck on a puzzle and don't know the solution. What do I do? You can figure it out. I believe in you. (And if it helps, the problem is almost never a matter of timing or finicky angling of portals; you're probably just trying the wrong thing. Shoot those portals somewhere else.)