I upgraded my backpack to the 2nd level one  ($5000 version one) and it initially works and holds more items.  However after saving my game and reloading it, it reverts back to the original version and only holds 5 items again at that point.

Hey man! Tested and confirmed! I looked at the code (it’s been a long time since I last opened the project), and tried to load a save file. It’s happening because the process to load the game, I actually spawn the player on a loading scene and try to give the player all the items he had at the time of the save game, but there’s a bug that, on my tests, it only “gives back” the tools the player had, and not the backpack or the items the player was carrying. I opened an issue on my source control project, but as I said previously and in my Youtube channel, right now unfotunately I don’t have the time to work on fixing this bug. Anyways, it really surprises me you opened 2 topics here. As I said, in the future I plan on releasing a new and rebranded game reusing what I’ve built on this project.