Beautiful art and interesting concept. I do feel like the platforming felt a bit unresponsive at times when I would be trying to move and jump at the same time.
Have to admit I didn't see the end. Trusted Umbra and didn't trust the happy old man so I was sent back to the beginning twice and didn't feel motivated to continue playing. Maybe if in addition to killing the player when they're tricked, something was revealed about the nature of the game world so it didn't feel like a random loss?