L the ProLogue to Death Note: Spiraling Trap is the third Death Note based game. The story is set before the plot of the original manga series. The game was to tie into the film, L: Change the WorLd.
The game plays like an escape room adventure game similar to 999: Nine Hours, Nine Persons, Nine Doors. The player starts the game by choosing their gender and name and after the intro, has to escape the dangerous building they've been trapped in. L appears on the top screen giving help as the player discovers tools to help them escape and disarm the traps. Certain traps have a timer that restrict how many actions the player can do to solve the puzzle. Some traps have multiple layers and require key items so, the player can stop in the middle of traps though it resets when they return.
There is an investigation mechanic with L where the player selects keywords and L interrogates one of the antagonists. This puts the antagonist on edge and can result in new information. Sometimes, the player is rewarded with a bluff that guarantees a "hit" instead of guessing keywords.
The game also includes a separate "L Communicator" mode in which users can make friends with L by giving him sweets. If the user succeeds in making friends with L, L will "talk" with the user via voice.
The player assumes the role of a rookie FBI agent who is knocked out during an undercover investigation. The player wakes up in a strange hotel and tries to escape despite the various traps laid out throughout the building. The genius detective L provides help in the escape via a fictional in-game PDA, and the player feeds L information that is gathered throughout the hotel and outside.