Mid level saving option was removed after test players completed the game in less than 4 hours.
'Hitman' was one of the first games to commission an entire orchestra to score the soundtrack (the Budapest Symphony Orchestra).
A removed one-liner spoken by 47 says "I feel like a Death Star", very likely being a nod to the Star Wars franchise.
Agent 47's bald appearence and the barcode on the back of his head were accidental. The developers struggled to create the hair, and decided to remove it from 47's character model. They also added the barcode to create a more iconic look.
Originaly meant to be called "Hitman: The Game", but later changed to "Hitman: Codename 47" to better highlight the unique protagonist Agent 47.