The door to Sach's hospital room is marked "214," but when Slip reads his chart, it indicates Sach is in room 302.
As with many movies made before the late 1950s, this one features a vacuum tube driven radio that comes to life immediately when it is turned on. In reality, vacuum tube devices took several seconds to warm up before any audio could be heard.
The radio Whitey tries to turn off on the counter at Louie's Sweet Shop is missing its power cord, as evident when he picks it up and shakes it.
Getting an on-premise liquor license for a restaurant is extremely complicated and time consuming. The quick change of Louie's establishment from sweet shop to night club probably didn't include looking into obtaining a liquor license. Rick, owner of a rival nightclub, should have been familiar with this and alerted the State Liquor Authority to cause them trouble, but didn't.