I enjoyed it! On the whole it was fun, and had a good level of challenge. As other people have mentioned, I thought the controls for the tree section were a bit frustrating at first, but it did feel very satisfying once I got over it. The wall jumping was fun, even though I wasn't very good at it, I can see there being a lot of room for mastering that mechanic! I also appreciated the generous checkpoints, I think without them the game could have been frustrating, so adding them in was a good choice. I also liked the colour choices for the sky and the stars in the last level, and the way you unlocked new mechanics as you progressed!
However, there were some things I think could be improved. As other people have mentioned, the jump sound effect was very grating and the music got very repetitive, so I'm sorry, but I ended up playing it with the sound muted. I also thought the visual effects with the snow and wind came on without any warning and were far too strong, especially the snow, it was actually quite difficult to look at and hurt my eyes a bit. I didn't like the fog effect towards the end either. The thing which is supposed to be fun and challenging about a platformer is the mastering the movement and layout of the level. Making it so the player has to squint at their screen to see where they're going didn't feel like a fun challenge to me, it felt unfair. I also really didn't like the camera movement, the way it snaps back when the player stops moving was very jarring and gave me a bit of motion sickness tbh. Finally, I think the backtracking after unlocking the tree climbing mechanic could have been executed better. I get that you were going for a metroidvania style gameplay, but in those types of games, usually you tease the player with an area they can't get to yet before they unlock the mechanic they need to progress, that way the unlock feels more exciting because they realise they can now get to a new area. Putting the spikes on the platforms leading up to the tree made it the less inviting path to take, so the player most likely went downwards first and already unlocked the tree climbing ability by the time they reach the tree, which made backtracking feel a bit pointless, like it should have been a linear level. I think it would have made much more sense to put the spikes on the other path instead, that way the player would probably see the tree first, need to backtrack, and unlocking the tree climbing would feel like a reward for overcoming a difficult platforming section.
Anyway, please don't let the negative feedback put you off, they're just things I think you could work on, but I enjoyed the game overall and I think there's a lot of potential for more fun gameplay! I look forward to seeing what you make in future! Good job!