20. The Worm Chase - Penumbra: Overture
https://www.youtube.com/watch?v=caMhgWA7Wkw These days, Frictional Games are known more for their work on Amnesia: The Dark Descent, but the Penumbra series is where the developers cut their teeth on the horror genre. By comparison, Penumbra: Overture may seem rough in spots, but the low-budget charm lends the game a certain rawness that really adds to the overall effect. It's the claustrophobic atmosphere that really sets Penumbra apart from other horror titles, and the game's focus on inducing dread through isolation ensures it's a good long while before you even encounter anything vaguely supernatural. And given Penumbra's iffy combat system, stealth is almost always the preferred option for dealing with enemies, making for some truly tense situations with one section in particular offering the game's best moment - after catching brief glimpses of the mammoth earthworm in earlier scenes, the creature finally makes an appearance in it's full glory; slithering after you as you scramble across numerous pitfalls.