Nightmare Fuel / Unreal

• The opening level. Prisoner 849 wakes onboard the crashed prison ship "Vortex Rikers". As the character, you sneak through the ship and are forced to watch a deadly, lightning-fast creature that is picking the last few survivors. You don't have a gun, and get brief glimpses of characters being ripped apart or begging for their lives just before finally escaping and getting a weapon. Special mention given to the electrocution chamber and the main controls room, where one of the chairs has a corpse... that screams as you approach it.
• In the third level, you visit a mine, and at one point you have to press a few buttons to unlock a forcefield. On your way back after doing so, one of the hallways you're walking through suddenly throws up a set of metal bars in front of and behind you, the lights go off one by one until you're in pitch darkness, and you hear a roar. Suddenly the lights flick back on blood-red. Cue your first confrontation against a Skaarj, a fast, bolt-shooting humanoid reptilian enemy with a leaping attack that you'll find quite a lot in later levels.
• The Gasbags look grotesque. They're floating, flying balls with black scaly skin, vaguely frog-like features, many eyes, an uncanny human-like pair of large muscular arms, and a huge, intimidating mouth out for your blood. It doesn't help that they favor dark places and become more common later in the game, with the only redeeming factor that they're fairly weak.
• Later, during one of the stages set onboard the Skaarj Mothership, you destroy its reactor. Once again, the stage plunges into near pitch-black conditions, only this time you're not blocked off from advancing, but instead have to navigate through a pitch-dark maze infested with all kinds of frenzied nastiness to get to the Skaarj Queen's chamber.

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