- Ace Harding's preferred brand of cigarettes (in the non-NES versions) is Lucky Strike. These are depicted with a white package with a red circle logo. However, until late-1942 (the games take place in December 1941 and 1942 next year) Lucky Strike's packaging was green, making this an anachronism.
- Technically speaking, organized crime didn't own or control any casinos in Las Vegas until 1946, also making the casino of the second game being a front for the mafia an anachronism.
- Newspaper Dating: The game puts the date of Ace Harding's adventure as December 7th, 1941, because a newspaper references the bombing of Pearl Harbor. At another point, the game won't let you enter a gun store because it's closed on Sunday. December 7th, 1941 actually was a Sunday!
- What Could Have Been: According to one Nintendo Power magazine back in 1992, Deja Vu II: Lost in Las Vegas was supposed to have been ported for the Nintendo Entertainment System in late 1992 (even the pictures for that version of the game were shown in the Previews section). However, it was never released (as it was probably canceled) and got stuck in Development Hell until it was revived for Game Boy Color as a part of Deja Vu I & II: The Casebooks of Ace Harding in 1999.
Trivia / Déjà Vu