Chex Quest 3

"Chex Quest 3 runs as a stand-alone game on ZDoom engine. Besides sporting the all-new episode in the series, the package also contains the revised versions of the former two (for a total of fifteen maps). The gameplay and core mechanics are derived from the classic Doom games - that is, it consists of exploring pseudo-3D maps through the first-person perspective, battling 'flemoids', searching for keys and solving button-based puzzles for a way out. However, the aural / visual style of the game is distinctly softer than its brethren thanks to the Chex-themed sprites and textures."