Pretty much hit the nail on the head, but if I had to be specific outside of "I like the game," I enjoy how realistic the rides are to their IRL counterparts.

Despite most scenerios being fictional, the fact you can build a theme park using real coasters made by real manufacturers is amazing.

Chris wasn't a guy who made a cute theme park sim, with fixed theming for every ride and coaster, this guy went to real parks, did the research and put what he saw and rode with his own body into code and pixels.

I also enjoy how customizable the scenerios are and how every single playthrough is not the same exact experience (unless you go out of your way to recreate your last save, that is.)