Below the Floodline

Cinevva's analyzer read this game's design doc and its source, then wrote the brief below. "Make your own" hands it to the game creator as your opening message, so you start from a real spec rather than a one-line idea.

Create a dark first-person 3D horror running game titled “Below the Floodline.” Use a Three.js-style perspective camera with a narrow 72-degree field of view, starting inside a claustrophobic flooded maintenance tunnel. The world should be almost black-blue with exponential fog, a heavy dark vignette, muted wet industrial surfaces, and sparse red emergency lighting. The player begins at the entrance and runs forward down the tunnel; movement is controlled with WASD or arrow keys on desktop, with mouse/pointer-lock or drag-look camera control, and jumping with Space. Support mobile controls with a left movement stick, drag-to-look, and a jump button.

Build a long straight sewer spine extending roughly 80 meters into the darkness along the negative Z direction. Make the corridor about 5.5 units wide and 3.8 units high, with a dark wet floor, low ceiling, and close side walls. Add occasional narrow rust-colored structural ribs that partially constrict the path, overhead rust pipes, grates, standing pools of translucent dark teal water across sections of the floor, and several irregular dark blood pools. Use repeating tunnel sections with blocked sightlines and a tight continuation/turn area at the far end, but keep the visible route primarily a straight, oppressive corridor. Place small red emissive emergency lamps along the ceiling at regular intervals; make their glow and intensity flicker over time. Light the scene with a very dim cold moon/fill light and two red accent lights, with shadows and fog hiding distant geometry.

The core goal is simply to run deeper into the tunnels while avoiding what follows. Track and display the maximum distance run in meters, calculated from the starting point. The HUD should show “Distance [number]m · run deeper” normally, and change the instruction to “DON’T LOOK BACK” when the pursuer is close. At the upper left, show the small spaced uppercase title “BELOW THE FLOODLINE.” At the upper right, show the red warning “SOMETHING IS MOVING BEHIND YOU,” with its opacity increasing as danger rises. Use a full-screen radial black vignette to make the edges very dark.

The signature pursuer is a procedural skeletal snake with a human-like skull: a chain of about fifteen pale bone rib/tori segments wavering through the darkness, ending in a skull with a rounded cranium, separate jaw, five small teeth, and two glowing red eyes. It begins behind the player and slowly follows, gently weaving side-to-side and bobbing. Increase fog density and danger feedback as it gets nearer. If the skull closes to roughly two units behind the player, end the run and show a centered dark translucent game-over overlay with a red-bordered card, the heading “IT FOUND YOU,” the text “The skull in the dark was not the worst thing down there.” and a “RUN AGAIN” button.

Also populate the distant tunnel with five zombie-like enemies using animated low-poly zombie models: three ordinary zombies at varying positions and two ribcage variants. They stand in the corridor and animate with walk/run cycles; after the player passes them, they slowly drift forward toward the player’s previous direction and sway slightly. Include four rusted barrels positioned near the walls as environmental obstacles. These enemies and props should add atmosphere; the actual coded loss condition is the skull pursuer reaching the player.

Begin with a full-screen intro overlay over the dark scene, using a blurred translucent black backdrop and a centered responsive card. The card has a subtle red border and dark red-black gradient, the large white uppercase title split across two lines as “BELOW THE / FLOODLINE,” the copy “The service tunnels were sealed for a reason. Run through the drowned maintenance maze. Do not look back for long.”, the small gray control hint “Desktop: click and use WASD. Mobile: left stick moves, drag to look, jump button.”, and a wide red-black outlined button labeled “ENTER THE TUNNELS.” Clicking/tapping it hides the overlay and begins play, requesting pointer lock on desktop. The overall art direction is restrained survival horror: nearly black environment, cold blue-gray illumination, wet teal water, corroded brown-red metal, pale bone, glowing red eyes, flickering red lamps, sparse minimalist typography, and no bright arcade UI.