Doubts about quality of wood-frame construction
None of this should be acceptable if you are paying someone to build you a shed.  Period.  Yes it passes inspection because it is not a habitable space, meaning that code wouldn't allow someone to live there so the only thing the inspector cares about is "Will this collapse and fall on someone?"

I am thinking you paid this company money based on a more stringent guideline of the building not collapsing.  I would make them fix each of these issues or tell them that you can find someone to do that and take that off their cost.  If you have not paid them in full you have all the leverage you need.  Any small claims court would not accept this from a professional company - it is not like you hired Joe from craigslist.  Now if you have already paid them fully, your beef still is right but good luck getting them to fix anything other than the window and rescrew door.