I did not fully read your description and didnt see that you didnt add enemies lol, I was on edge the entire time. For feedback:
Fun: It was fun, it did miss some elements but then again your audio did make up for a lot of things, the house was a bit anti climactic I feel like if youd add some sort of fire just beside the map or burning trees and added the story of finding your friends to escape it would be really cool. The idea you had is better but since you didnt have time I feel like a bit more story instead of more mechanics wouldve made it even more fun.
Core elements: I really like this spin and like I said also the idea. The save your friends is just perfect and very creative! Maybe some different silhouetes (idk how to spell sorry) wouldve made it bit more engaging but you did perfect for the criteria!
Polished: I did see some mistakes in the art, the left corner some trees were off and then also the feeling of some content missing. But the content that you had was amazing
Audio: You nailed it, like i said at the start I didnt read your description so I did not know there werent enemies and I was genuinly scared to whistle lol. This feeling can only be made by a great combo on audio and design so you nailed it!
UI: Ui was good no real remarks here, only thing I can think of is having the character swap in the middle of the screen could be bothersome if youre getting chased.
I really like this idea and I do wish you could finish it! Good job!