1. It's possible to view your character from GLaDOS' perspective at certain points in the game.
2. Chapter names include 'The Surprise', 'The Fall' and 'The Return'.
3. The recent Potato-themed promotion has more relevance to the game's story than you might think.
4. "You don't know pride. You don't know fear. You don't know anything. You'll be perfect."
5. Jonathan Coulton, writer of the song 'Still Alive' from the original game, has written a new track for Portal 2. And yes, it plays during the credits. We recommend you don't hear it until you've finished the game, though...
6. You'll see more than one version of the Aperture Science logo in the game. More than three, in fact.
7. "This statement is false."
8. Wheatley proudly claims that he has read Machiavelli.
9. There's one particular test chamber you have to perform twice.
10. There is no cake in this game. Or is that a lie?
Are you looking forward to Portal 2? Or have you already started playing it? Add a comment to the space below!