I can't put Hollow Knight down. After I've been playing for a little bit, it has a real knack to get me to say, let's just go down this path to see what's down there. Then, I'm that far into it, so I should find a bench. Then, I find the map and you know what, I bet if I go down this path I will unlock the shortcut. Oops, I died. Well, I should go get my Soul back and get that shortcut open so I can start fresh next time, but I'll just give the boss a try. Oops, died, but I bet I could beat him next try. Oops, died, but you know what I bet switching up the charms would get it done. Beat them which opens up a new area, so let me just go down this path to see what's down there...
Finding new areas and hidden paths is really satisfying. Getting new skills to be able to go back through areas is also satisfying, but I wish I did a better job of marking the map. I like the whole Soul mechanic of using it to regain health or cast spells and getting it back by hitting enemies. The bosses are fun and challenging without being punishing (so far anyway). The charms might be the first RPG-esque element in a game I've played that I actually like.
The only thing I don't like is some of the platforming, especially around spikes. I find it incredibly frustrating and I don't really feel a sense of accomplishment when I finally get past it. It's more just relief I don't have to do it anymore. That's probably a me issue more than the game, though.