Right, so I decided to go back and play through the game, and finished it this time. Further notes:
4. The background flashing red when you die is a really simple effect, but it looks nice! Which is good, because I saw it a lot.
5. It feels weird that the player character doesn't turn when they move in midair. This occasionally has an effect on gameplay—sometimes right after landing, I throw my BUDD the wrong way.
6. The art direction is great. The way that sci-fi-industrial aesthetics are blended with overgrown green-and-pink plants really works.
7. The floating turret enemies are a pain in the butt. You can't fire in midair, so unless there happens to be a nearby platform at the right height (which there almost never is), you just have to endure or dodge the bullets. Which is fine if you're just running past, but if you're trying to precisely place the Coil or you fall in the wrong nook (with a bullet always blocking your path if you try to leave), it's...not.
8. Much as I dislike the turrets, adding them throughout the world after getting the third BUDD helps make that last segment of the game feel less repetitive. The East Forest full of fiery death bullets is WAY different than the East Forest with just fire-breathing flowers and shambling vine-monsters!
9. The controls work pretty well, but with the three action buttons be right next to each other like that, I kept hitting the wrong button by accident. Dying because a deadly flower knocked me into lava? Annoying, but that's an NES throwback for you. Dying because I switched BUDDs instead of jumping, or jumped instead of attacking? Quite annoying indeed. Why do so many games do that?
10. The ending slides were cute.
See you next game, I guess!