Also had a dream about another Hitman level
The overall location was an American city, a lot of 3 story red brick buildings and all connected via alleyways and subway tunnels. Other locations connected to it.
A high-tech futuristic hospital, a strip club and an East-Asian mob hideout. The target was the mob boss, an old man.
You could kill him in multiple ways, one being dressing up as his doctor (see the hospital) or getting his mistress (see the club) to kill him herself.
I remember one bit in the hospital where you can encourage a doctor to check out the end of a hallway that had its lights burnt out.
You didn't need to lure him you just needed to say “get go down the hallway" and he'd do it, where you could knock him out and hide his body in a closet.
I also remember there being side quests about tracking down some artifacts and finding hidden rooms around the city