I don't know how others feel, but I think this is a really solid entry due to its simplicity. This is the only game I played before the jam started so I gave it another go just to see what might have been changed.
Theme-wise and sensory-wise, I think you did well with the joint theme of "cozy" and "hell". While you did have so darker colors, the majority were lighter which did give me a sense cozy, while still clearly communicating the Hell aspect.
Metroidvania-wise, you did well in the sense that it was perfectly clear the paths you had to take and the places you notice you can't reach yet. You don't even need a map. Kudos.
The only thing that sticks out negatively is the background. In my opinion, thats needs a bit of work or be a solid color.
I highly recommend continuing this project for the SMVM. I feel like you have a solid leaping off point to pivot to a whole different game or plenty of time to expand this entry. Great job!