Déjà Vu is a "point-and-click" adventure game set in the world of 1940s hard-boiled detective novels and movies. It was released in 1985 for Macintosh – the first in the MacVenture series – and later ported to several other systems. It was also released on Commodore Amiga and featured more sophisticated graphics in 1985-87.

The game takes place in Chicago during December 1941, shortly after the attack on Pearl Harbor. The game character is Theodore "Ace" Harding, a retired boxer working as a private eye.

The player awakes one morning in a bathroom stall, unable to remember who he is. The bathroom stall turns out to be in Joe's Bar. A dead man is found in an upstairs office, and Ace is about to be framed for the murder. There are some clues as to the identity of the murdered man and to the player himself. A strap-down chair, mysterious vials, and a syringe are found, suggesting (together with a needle mark on the player's arm) that some kind of elaborate torture has taken place.

Adversaries that the player meets outside the bar is a mugger, an old acquaintance with a grudge, and the police. The player has a boxing background which proves a valuable asset. The player must find addresses around Joe's bar, and then make taxi rides to a few locations, including his office to gather more elements and unravel the story. It involves a kidnapping in which Ace has played some part, but his memory lacks important details.

Ace's memory and mental condition get progressively worse, so the player is required to obtain an antidote to the drug that caused the memory loss. After that, Ace has recurring flashbacks filled with information the help the player to evaluate the evidence and take action accordingly.

This game and its sequel, Deja Vu II: Lost in Las Vegas, require significant lateral thinking. Some situations are based in common detective techniques, while others require simple violence. Overall, they are more realistic than the two other MacVentures titles (Uninvited and Shadowgate), because there are no supernatural events involved.