If you have an Xbox 360 or Xbox One, and you have an Xbox Live Gold account, be sure to grab Portal: Still Alive for free before June 15th, 2019! More info is here.
The game is over a decade old now, but the puzzles and writing are still superb even if the graphics and game engine are showing their age by current standards. If you have somehow managed to not encounter this gem of a game before, you're in for a treat. Back when this game was new, I had little money, but I wanted to see what the hype was all about, so I pirated the game for my computer. I played it, and then promptly went out to buy The Orange Box collection at a retail store (remember when that was a thing?) because it was that good.
The story is simple. You wake up in a strange sleeping pod in a pristine research facility, and a robotic voice tells you to solve some puzzles as part of a research project. You eventually acquire a device that allows you to create portals between different surfaces so you can make your way through the environment with your own wormholes. The puzzles become more complicated, and then the story takes a twist and sends you though the industrial underside of the facility to confront someone trying to kill you.
Any more details than that would spoil too much. Trust me, the dialog is superb. Most of the game can be pursued at your own pace, although there are times when timing is essential. It's not very long, and even a casual attempt only takes a few hours. This assumes you don't get stuck at one of the puzzles that had an obvious solution you overlooked for ages. None of us ever encounter that experience though, right? The Xbox port also includes some special challenge levels, so if you fund the game easy, or want a new opportunity to think with portals, you can try for time trial mode and beat some truly twisted puzzles.
In short, get this game. If you don't have an Xbox, watch for Steam sales or Playstation store sales and grab it when the opportunity presents itself. Check used game stores and pawn shops for the Orange Box collection too, because Half-Life 2 is a great game as well. The version of Portal there is the same game, just with different achievements and no challenge levels. The only downside to the console versions seems to be the absence of the updated ending animation that teased Portal 2 on PC.