The player views the action from a first-person perspective and guides the space marine through interconnected map episodes. Each level requires finding keys, opening routes, surviving ambushes, and reaching the exit; optional secret areas reward exploration.

The marine can run, strafe, fire, switch weapons, use doors and switches, and consult an automap. Weapons and ammunition are collected during missions, while health and armor provide limited protection. The four episodes contain progressively tougher encounters, with difficulty settings changing enemy damage and the amount of opposition.

Preserve powerful ammunition for large enemies and dense ambushes, but avoid hoarding so much that you enter later fights under-equipped.

Search for unusual wall textures, recessed panels, and dead ends. Use the automap to identify unexplored branches, and circle-strafe around large enemies while keeping moving.

For Thy Flesh Consumed, learn the opening routes before attempting higher difficulty. Retreat through cleared areas when necessary instead of fighting every enemy in confined spaces.