1.
Star Wars: Knights of the Old Republic
(Guessed by Conegamer)
Knights of the Old Republic isn't the game I've replayed the most. It has somewhat aged decently, although with a few missteps along the way. Its graphics are starting to show its age. It still features some of the strangests bugs in gaming history.
And yet...and yet! This is the most enjoyable experience I've had on my gaming career. Every single area is done in an exemplary way, whether it is the superb plot (I dare to say, this game is even better than its original source. Heck, KOTOR is better than anything else on the Star Wars universe, with maybe Jedi Outcast and The Empire Strikes Back matching it), the outstanding gameplay system, based on both traditional D&D structure and the player's skill and strategy, the character interaction and developing, the memorable Star Wars soundtrack, the lively planets waiting for you to explore and the plot twist that, while overused nowadays in a lot of media, was groundbreaking for its time (Probably one of the few times I've had massive goosebumps while playing a game). It's hard for me to describe this game without being all biased, but that's just because of how much I love it. How much I've spend in its world, and doing all the possible outcomes regarding who you are and what mission you're doing.
If that doesn't convince you, well...
This game features the very first lesbian relationship in Star Wars!
No?, well, how about...
This is the only game I know that allows you to defeat the final boss by transforming him into a Twi'lek and defeating him by dancing.