The first game with a way more in depth emotional storyline. Psychonauts 2 is better than 1 with its story and most characters, but I did find level themes to be lacking than the first game. None of the levels in this game are bad, but Milkman, Lungfish, Black Velvet, and Waterloo were way more striking to me. Psyconauts 2, however, makes up for that in how the levels tell a story, and they are usually pretty damn good.
I do find the Camp to be more interesting than the real life segments in 2. I also remember the camp kids having more going on than the interns in this game. Like some of the interns have stuff going on, but it feels just a little lacking.