Diabolical Nightmare is a series of three games designed to be dark, eerie, and full of action. Travel through multiple levels of eerie ambiance and kill all monsters in the level to advance to the next level.

Three games are included:

Diabolical Nightmare 1 was released way back in 2010 and was a spooky PSX doom inspired game using the DC Tech Three game engine, the objective of the game is to kill all monsters in each level to proceed to the next.

Diabolical Nightmare 2 was released later on that year, with more linear gameplay. Instead of killing all monsters, you had to find the exit to the next section.

Diabolical Nightmare 3 started back in 2011, right after the author had released the second game. However, due to a hard drive failure, the game was lost. A year later they decided to start the game again using GZDoom but hadn't touched until 2017. DN3 is currently a demo that lasts around 15 minutes, at some point, you'll run into a dead end.