There's two things that primarily make me love this game, and they're things I wasn't really expecting when starting out.

1. Progression feels extremely good. The feeling of hitting a wall with a boss and doing your absolute best to persevere despite the setbacks and eventually succeeding is some weird mixture of exhilaration and relief, and it's awesome.

2. Throughout the game, I felt as if I was having a conversation with Miyazaki himself. It's especially the case in the first half of the game, where the game is constantly teaching you new mechanics and ways to avoid traps and the like. Most people mention that the game falls off in the second half, but I think that's only half true. Lost Izalith is clearly unfinished and New Londo is obnoxious, but I quite enjoyed the Tomb of the Giants and the Duke's Archives. In general though, I do think the game is strongest in the beginning up to Anor Londo. The game is constantly teaching you new things and Miyazaki is a marvelous asshole.

Awesome game and a great start to my FromSoft journey :)