Thank you so much for the detailed feedback! And those aren't stupid questions at all :) In fact, it's really useful for me to know which mechanics weren't clear enough without an explanation.
The items that appear below the doughnuts (the hunger bar) are actually a list of ingredients. You can find them in chests and use them to craft different kinds of food. In the tutorial level, you need to reach the shelter first, where you'll find a special microwave that you can use for cooking. Different foods give you different buffs, including restoring your hunger. But don't use up all your food — you'll also need some of it to upgrade your character later on :)
As for the Crystal Key, you're on the right track! It can only be seen in the light of your flashlight, but the crystal itself is always somewhere in the fog. So once you reach a foggy area, that's when you should start looking around carefully with the flashlight. In the tutorial level specifically, you'll find it behind a door that you need to unlock with a key. Your feedback made me realize that the game probably doesn't communicate this clearly enough.
And no need to apologize for the questions — if a player isn't sure how something works, that's useful feedback for me as the developer :)
About the shadows: if you mean the reduced visibility behind the player, then yes — that shadow effect is made with a custom shader I created for the game :)
Thanks again for playing and for taking the time to write such detailed feedback! I'm really glad you enjoyed the mechanics and overall feel of the game. Hopefully these hints will help on your next attempt! :)