I just got Portal off of Steam, and it's AMAZING. The first achievement I beat was "Terminal Velocity" , in which you have to fall thirty thousand feet using consecutive portals. I am currently trying to do "Long Jump", to do this you must jump forward 300 feet. The final level (which is really seven levels crammed into one) is the escape part. When you beat it you're treated to a hilarious song that you can hear for free at newgrounds. com/portal/view/413839. Altogether great game, where your brain skills are just as handy as your reflexes.