Hi hi!
After some consideration, we added a saving feature to the game. Collectibles will now be saved once you find them. Items won't be, however.
We're now also keeping track of whether you've defeated the warlock, however, this is not yet displayed. We're working on a broader in-game achievement system, as well as connecting these things to Steam achievements.
More updates are on the way, including some bigger content updates. Be sure to join our discord if you'd like to pitch your ideas for future updates.
See ya!
Stijn