I bought Portal: Still Alive off Xbox live Arcade, because I remembered the game getting a lot of positive buzz when it first came out many years ago.
It's a puzzle game, as you're sent through a series of rooms where you have to figure out how to get to the door to the next room, all as a tonally pleasant computerized voice tells you various things. Most of which are either lies, or disturbing if true.
I wouldn't say figuring out what to do was the hard part, which is usually the case for me with puzzle games. It was getting the portals in the right spot to do what I needed, in the time frame required. There were a lot of times I was sure I put the portal in the right place but no, too high, or too far to the left, try again. I did get a little dizzy with the puzzles that involved needing to drop through a portal. The portals must have a "top" and "bottom", because sometimes I'd go through them and as I was moving through, the character would get flipped or rotated. Which made it hard to get my bearings as I'd exit the portal. Which made it hard to try and direct my fall, or shoot my next portal where I needed it to go. Which wasn't a problem I'd expected going in. Probably should have, given it's a game all about taking advantage of physics.
I pretty much finished the story mode in an afternoon. Got stymied at one spot (it turned out I was overthinking it, making the solution too complicated), called it a day, finished the next night. I guess I could try Challenge Mode, but there doesn't seem to be a story involved in that, just more puzzles. And without some motivating reason, I'm not really that interested in messing around with the portals just to mess with them. Solving the puzzles to get my character safely through this shop of horrors was a decent motivation.