I.e., games that hooked you in and you couldn’t stop playing until it was finished. Not games that just happened to be unexpectedly short. And by “completed” I guess I mean the main story etc, not 100%ing the game :).
For me, it would be Catherine, Bioshock Infinite and Black Mesa (although I think I got to the final area then had to go to sleep and complete it the next day). I also played an ungodly amount of Hades in one sitting, but didn’t get the “full” ending in one day.
Spec Ops: The Line. I started playing it in the morning, the story kept me engaged (and the gameplay was fun enough). I played it all day to its conclusion.
Ironic!
Why?
Because it’s a game that’s constantly telling the player that they should stop playing it. That everything is going to get worse if you do and it’s all your fault. That you’re going to cross the line again and again and again until every single person in the game is doomed. And then we play through the entire thing anyway, because it’s so fucking good.