I'm sorry you felt that way :(
I'm currently trying to update the cave system/Buildbag thing to be less confusing after getting similar feedback, so you're very right about that :/ . Though please remember that this is a very very very early demo of what will probably be a long game. All of this stuff you mentioned will absolutely be worked on and polished in the future!
You can save your game by pressing Esc at any time. I intended the player to save often as dying will reset you to the last save (I will probably add this to the tutorial soon).
The money making thing is also currently in a very under-baked state. In the future you will have to actually sell your items (instead of getting money right away) and your character will have a job (plot spoilers), this current money making system is just a placeholder at the moment.
Also Gypsum crystals are real, I didn't name it like that lol
Anyways, thank you so much for your feedback!! Stuff like this is how bad games become polished ones, so thank you for not holding back honestly lol <3