I beat it in one sitting yesterday. Won't say too much because spoilers, but I really think Toby deserves more credit for his ability to do really subtle character writing. Outside of the big obvious stuff, there's a lot of little moments that make the bright and colorful adventure feel "off," even if you don't go out of your way to be evil. Undertale had this too, but I enjoy the way it really feels like there's more going on beneath the surface of the story. Toby is especially good at "secret horror," for lack of a better term. The secret boss is probably my favorite character, everything surrounding him was great. A real mix of comedy and dread. The secret story route you can take is also just plain disturbing, in a way not even the genocide route of undertale was. Good stuff.
As for more normal things, the comedic dialogue is great, chapter 2 introduced a lot of little quality of life improvements, and some new incentives that keep the gameplay a bit more interesting. Ralsei and Susie can also ACT now, which was a feature I felt was lacking in the original release, and you can see how much more "mercy" is needed to end a battle now. I hope he keeps iterating on the system to keep the future chapters as fresh.
Also, don't forget your tree egg.