I finished Celeste yesterday by climbing to the top of the mountain. It's one of the best games I've ever played.
I loved the game design. It's platforming at its best. The game has very basic mechanics: jump, dash and climb. To succeed it requires a lot of quick technical movements that ask for patience and timing.
The puzzle aspect of figuring how out how to use the mechanics to progress to the next part of the map is something I really enjoyed. It hooked me in big time.
I think only 2 dev's worked on the programming of the game which is a phenomenal achievement. Maddy Thorson was the lead dev and she deserves all the plaudits.
I like that some of my money paid for this game is going to a small team and not some big faceless corporation.
The game story and dialog surprised me. It's by no means deep but it has some really nice messages about how to handle anxiety and trusting in yourself and your own instincts. I think it expresses a really positive message.