There's something very pleasant about how you've presented this game with the music and nature. The initial vibe is nice!
From a technical standpoint, I'll admit this game is pretty rough around the edges. The collision-handling can be a little finnicky (I don't
think wall-jumping was intended!) and the immediate transitions can be a little jarring. I get the impression, though, that the physics logic was put together at a pretty low-level, and if that's the case you've done a pretty good job getting everything to work. Having moving platforms that
mostly work is actually quite impressive!
It'll help a lot for myself and other critics to share a bit more about your level of experience and the tools you're working with, as it's hard to know what kind of advice to give without that frame of reference.
It'd also be nice to feel like collecting butterflies makes some difference, even if it's as simple as displaying "perfect!" at the end of the game. As it is, it doesn't seem to make much different whether I collect all butterflies or if I don't bother at all.
Going into future projects, you may want to do some research into some of the Physics stuff, as tightening up these issues would go a long way into having a more polished-feeling game. Rodrigo Monteiro's
Guide to Implementing 2D Platformers was really helpful for me back when I was playing around with platformers.
Other random observations- Having a bright yellow butterfly right at the beginning is actually an excellent design choice. It's immediately the most noticeable thing on screen and my immediate reaction is to grab it, thus teaching my the central goal of the game.
- The animations are quite nice! I think a lot of that atmosphere stuff I mentioned comes from how natural the characters movements are.
- It's a bit hard to read where my hitbox is. Juno has a pretty long frame and it's not immediately obvious whether the tail and the neck are part of her collision. Because of this, it's tricky knowing how close you can get to the dogs without dying.
- I really liked what you've done with the crow behavior! There's a moment of intimidation when you first see how they move, but it's simple enough that you can quickly figure out the timing. It was actually very satisfying as a player finding the "safe spot" between two crows and having the game acknowledge this by not killing me when I ran to it. The last stretch is scary to run through, but actually pretty easy to pull off. Very well done with these!
Overall, there's definitely a lot of polish needed, but I believe you'll improve at that with more experience. This was a simple little game that made me smile, so kudos to you.