Hellgate 1993

Hellgate 1993 takes place inside a dying horror-sci-fi facility. You fight through eight hostile worlds and try to bring the light back to the last surviving human signal. Each world is split into three stages: two combat missions followed by a boss encounter, so a final boss waits at the end of every world. New enemy types appear as the campaign goes on, and you have to manage health, armor, ammo, keys, and your arsenal to keep going.

Every world follows the same three-stage structure: two combat missions, then a boss fight at the end of that world. Along the way you find hidden supplies, activate terminals, survive ambushes, and unlock sealed sectors. Secret routes are hidden inside the levels, and stronger weapons can be collected as you advance.