Gatefall

Premise

The tunnels are rising. The city is sinking. And you’re the only thing standing between salvation and catastrophe.

Gatefall is a fast, punchy, one-page RPG set in the flooded maintenance labyrinth beneath a sprawling cyberpunk megacity. Toxic water churns through ancient pipes, dissolving anything synthetic it touches. Bioluminescent predators stalk every flicker of power. And somewhere in the depths, a colossal flood-gate valve—older than the Collapse—grinds toward total failure.

You’re a crew of tunnel-runners, divers, splicers, and patch-techs sent to repair it before the lower districts drown. Succeed, and you uncover a hidden cache of pre-Collapse technology capable of turning you into a cybernetic powerhouse. Fail, and the rising water will take the city… and you’ll take the blame.

Playable with friends or solo.

You’ll navigate overgrown tunnels, patch decaying systems, face glowing swamp-creatures hungry for electricity, and race against a ticking Water Clock that measures how close disaster really is.

Great for one-shots, pick-up play, and fast improvisational sessions.

No prep. No bloat. Just neon-soaked tension, weird ecology, and high-stakes problem-solving beneath a sinking city.

Features

• One-page, rules-light system (2d6)
• Solo and multiplayer support
• Rapid-growth plantlife meets retro-future tech
• Creatures that hunt power, not flesh
• A rising-water doom clock keeping the pressure high
• Repair puzzles, tunnel hazards, ancient machinery
• A twist: the “toxic” water is actually life-giving—just not to the city

Perfect For

• Fans of cyberpunk with a weird-ecology twist
• One-shot nights and convention tables
• Players who enjoy environmental storytelling and problem-solving
• Designers looking for a clean, tight micro-RPG structure