I really like this! The fact that there aren't any bushes in the first place is definitely my favorite part, but I also appreciate how you were able to convey the character emotions within the bounds of their original designs (I don't know if this is impressive or not, just something I think I had trouble with at one point). The framing of the scenes are also pretty good.
Outside of general refinement of your style, the only real suggestions I'd make is 1) having the close-up of Undyne grabbing Napstablook be from the front (so the arm is obscured) to better lead into the next panel, and 2) spacing out the final panels (Alphys in the restaurant and the impact) so there's more anticipation between the panels. You don't even have to expand the scenes that much, you could just make another page and leave the empty space empty.
For the "refining your style" part, I've heard that studies are the go to, and I'd suggest limbs and how they interact with perspective.