Stunning! This is perfect given the time frame, and both a lovely idea and a lovely execution.
I would really enjoy if you added more decorations and a little more open-endedness, this is a fun experience that I think is worthwhile :)
I do have a few minor notes in case you do want to keep working on it, but it really is great as is...
1. I was a bit confused on why I couldn't leave before realizing you can't leave while roasting a marshmellow
2. I didn't understand quite how roasting marshmellows works right away, and it took me about 4 minutes to understand that you can roast them faster with a bigger fire
3. Fishing was not immediately intuitive; I lost a couple before realizing all you had to do was click the rod while the fish is in the green area.
4. I'm not exactly sure how warmth works; I know that eating a fully roasted marshmellow works, but it seems like I got big increases (even bigger than from eating a marshmellow) at other times that I couldn't explain, but was very thankful for...