People who have finished a game in one sitting,

what game did you finish and was it worth it?

You mean for first time or in general?

I don't remember finishing anything straight from starting to play, except arcade games on emulator (where you effectively have infinite coins=lives/continues).

On the other hand there are some games I have played on one sitting - some of us are old enough to remember time when there rarely was a choice to that...
I've rarely done it when there is a choice. Most notable examples are my old favorites Wing Commander and Monkey Island. On some driving games (Fatal Racing) the major series mode only takes hour and a half, so that kind of thing I've played numerous times. Master System Asterix is one old platformer you have to do at once, no save available.

First game that I legit never got up til I beat it, was Zelda Link to the Past. I couldn't put it down when I first played that game. And now I'm learning how to speedrun the game now.