Changes after loading

I have a question regarding the loading of saves. Why does the World partially reset and/or change everytime you load into the game. I noticed that locks on doors that you have opened are locked again, or that dead bodies of any kind dissappear, but looted crates remain looted? That to me is the most immersion breaking aspect of the game and that sometimes discourages me from playing when I know something big that I have achieved, Like defeating a boss in a city that I can now loot, will be undone, as soon as I load back into the game. Due to it being a more or less handcrafted map that one gets to explore, the feeling of actually having an impact on the world around you is sorely missing.

What is the reason for this? Is it maybe due to technical limitations? I know its just one guy making this game and what we have so far us absolutely amazing.

Would love to hear what you all think about this.