Best:
Factorio - The factory must grow.
Vampire Survivors - They keep releasing new content, and I keep devouring it. This game is even more addicting than Cracktorio.
The Murder of Sonic the Hedgehog - Best April Fools joke this year, and a solid light visual novel in its own right. This was a pleasant surprise.
Remnant II - My choice for Game of the Year this year. TotK let me down, and while BG3 is solidly in the #2 spot I don't really vibe with it. Remnant II is an excellent sequel that builds on the strengths while fixing the weaknesses of its predecessor. It's a hell of a game that still manages to stand out in a year stacked with great titles.
Note: I didn't play AC6 or the new Street Fighter, so I've got no opinion on how they match up.
Worst:
Keywe - A puzzle game where you play as Kiwi birds managing a post office in Australia. Not my thing, but my sister likes it and wanted to play the multiplayer with me. We played online and holy hell this game's netcode is broken. We kept desyncing mid-puzzle and then whoever was hosting would have to finish the puzzle while the other stood and watched because they couldn't see the actual gamestate. It's probably a fine game as a solo or local play experience, but it left a sour impression.