The visual style is good and is going in the right direction whilst a lot of improvements need to be made I'm sure your artists is well aware.
Blurring the background is nice but I'd also change the saturation to make some more contrast between the foreground and background as well as adding a lot more depth.
A lot of the UI elements over use gradients which ends up making them look cheap, maybe some more textured elements could look better.
The wolf attack pulls you forward into enemies which also damage you on collision, this attack needs knockback to feel good. At the moment it is very awkward to use and the wolf does not feel more powerful than the hare who can easily avoid enemy damage with the goomba stomp.
After unlocking the gate as the raven the world collisions broke for me. I stepped back from the gate and fell through the ground and I was stuck outside the map.
After failing the jumping on enemies puzzle the enemies didn't respawn and I couldn't retry the puzzle.
As others have mention the foreground elements hide the player, although they add a good sense of depth the player needs to be visible with some kind of outline through them or they could fade out slightly when overlapping the player/enemies.
I'd also add some vertical paralex on the background so that when you get higher in the tree tops the background moves down so that it actually feels like you've gone higher in the world.
I'd also like there to be more difference between the forms, movement should feel different for each one. It felt to me like both the wolf and the hare were moving at the same speed but I expected when I switched back to the hare I would bounce along the ground and move faster. Perhaps more unique animations for their walk cycles could help differentiate them more and give them some unique personality each.
Very nice start so far and the concept could be great if you keep working on it.