Thank you for taking the time to play the game and leave such good feedback! I think getting a tutorial in the game would help with explaining things (still kicking myself for that) - but I really liked how you gave some suggestions to make things more intuitive by itself, without having to tread some text or something. We want to do at least 1 post jam update so I'll give some more thought how to use that approach (with the thought bubble, or drawing attention to the timer)
There is a way to craft upgrades in the cave at the tree in the corner. You can get 10 more inventory slots this way, but I had gotten feedback that most of the upgrades were as difficult to craft as the main quest items, so I think I need to do some rebalancing.
Sorry about the cave and resetting your items! That 100% was going to be explained in the tutorial in my head, but I can see how that happens (I didn't even get any visual indication when the day timer was running low). Thanks for playing and again for the feedback. I love playing crafting/survival games, but this was my first attempt in the style.