Resident Evil (GameCube) | The Aqua Ring
In the original Resident Evil, your run-in with the Umbrella Mansion's zombie sharks was brief, mildly frightening and took place in a room that was flooded to about waist height because the sharks had managed to break out of their tank. The Resident Evil GameCube remake features a similar scenario, except that now the "room" is the Aqua Ring, a massive, circular tank built in the middle of a huge observation chamber. And this time, the waist-deep flooding goes up to the chamber's flimsy catwalks, as a school of zombie sharks circle menacingly just underneath. But the king bastard in the room is the massive Neptune, whose shadow you can see far below all the other sharks, and if you don't move your ass, he'll bite it right the hell off:

The key to not ending up fish food here is to move as fast as possible and find a switch to drain the water from the room - but even then, you're not out of the woods. Neptune, seemingly dead, stands between you and a key you need - and once you grab it, he wakes up and starts trying to eat you. It's a frightening thing, having an angry mutant shark thrashing around right in your face, and if you play your cards wrong, well, this happens:

Resident Evil 4 (PS2, Wii, GameCube) | Chapter 2-2
The greatest section in Capcom's superb Resi reinvention, joining the game's heart-pounding pace and violence with a claustrophobic no-way-out scenario, has to be the moment you're trapped in a wood cabin at the end of Chapter 2-2.

Waves of infected villagers claw their way inside the cabin, as you sprint around desperately hauling wooden barricades against the breached windows. Eventually, the flimsy barriers explode into splinters, and the wailing nasties are all around you. Even with the surprisingly effective Luis watching your back, the sheer numbers of zombie-like enemies that swarm into the building are daunting - especially when what you thought was a lucky headshot turns sour, as the parasite infecting your victim bursts from their neck, all sharp and swingy.

You're forced back, up the stairs to the next floor - where the fanatical enemies start using ladders to crash through the windows. Gamers who lack soul might already know (or have worked out in their android-like approach to gaming) that you only need to kill a certain number of villagers to finish the siege. For the rest of us, though, the seemingly endless, nigh on unstoppable tide of slavering, fleshy blade-headed monstrosities makes for a breathless and unmissable Resi romp.

Rez (Dreamcast, PS2) | Area 4 Boss (Uranus)
It's the future. You're inside a computer navigating a super network and battling the viral minions of a suicidal artificial intelligence. It's techno organic transcendental gameplay at its most pure. It's a 5am retro-futuristic rehab for drug casualties. It's vibrating wankware for the ladies. It's pulsating geometrical shapes and laser beams. It's a giant digital man running through corridors. It's Joujouka's 'Rock is Sponge' banging electro tribal rhythms in your earholes. It's 100% Analyzation. It's what videogames should be.