The concept works well and there's a nice tension build-up. As with most of these jam games there's always room for improvement so here are my two cents, if you plan on building on this prototype:
- Was it a personal choice not to show how much "health" you got left once in the cold ? Maybe have the character trembling, or just a small visual cue to tell you the player that he's almost dead.
- First enemy wave can be brutal, maybe work on the difficulty increment.
- I found that I was longing for the ability to build other bonfires to progress through the night.