Trail Rush

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 browser-playable 3D endless downhill trail-dodging game titled “Trail Rush.” Use a third-person perspective camera behind and slightly above a small bicycle, looking forward down the course. The scene has a pale sky-blue background with matching distance fog, soft shadows, bright hemisphere lighting, and a simple low-poly outdoor style.

The course is a long straight brown dirt trail, represented by a wide flat strip extending into the distance. Put broad green grass banks on both sides and narrow off-white snow strips along the trail edges. The player rides near the bottom-center of the view on a small stylized bicycle: two dark ring wheels, a red frame and front stem, dark seat and handlebars, and a very simple rider made from a peach-colored spherical head/body detail with a blue helmet. Keep the bike visibly small and toy-like, with basic geometric modeling and shadows.

Make the game an endless forward ride. The bike stays at a fixed forward position while the trail and obstacles appear to move toward the camera, creating downhill/forward motion. Start on a centered title overlay: a dark translucent rounded panel with the heading “Trail Rush,” the subtitle “Ride fast. Thread the gaps.”, and a yellow rounded “Start ride” button. Behind it, show the game scene and HUD. The top-left HUD is a dark translucent rounded panel reading “TRAIL RUSH.” The top-right panel displays two lines, “Distance 0 m” and “Best 0 m.” Centered near the top, show the instruction “Dodge trees and rocks — stay on the trail,” with desktop steering guidance for left/right arrows and A/D.

When the player starts, hide the start overlay, reset the bike to the center and reset the distance for that run. The ride begins at speed 9 and gradually accelerates as distance increases, capped at speed 18. Increase the distance continuously according to the current speed and show the rounded-down meter count in the HUD. Persist the best distance across browser sessions and update it when the run ends.

Steering is horizontal only. Arrow Left or A steers left, and Arrow Right or D steers right; support simultaneous press state cleanly, with right taking the positive direction and left the negative direction. Also provide mobile/touch controls at the bottom: two dark translucent square buttons with white left and right triangle icons, held to steer while pressed. Clamp the bike’s horizontal position to the trail area, approximately -4.65 to +4.65. Give the bike a subtle banking/lean animation toward the steering direction. Keep the camera subtly following the bike’s horizontal movement while looking ahead down the trail.

Spawn obstacles ahead on the trail and move them toward the player. Each spawn should occur around z=-42, with a random horizontal position from approximately -3.8 to +3.8. Randomly choose either a pine tree (about 58% chance) or a rock. Trees should use a low-poly pine-tree nature asset if available, scaled around 1.45; rocks should use a low-poly irregular cliff/rock asset if available, scaled around 1.1. If external assets are unavailable, substitute a simple green cone-like tree and gray faceted rock. Occasionally spawn a second obstacle farther ahead around z=-49 at an offset position, so the player must thread gaps. Start spawning after a short delay and gradually reduce the spawn interval with distance, but never let it go below roughly 0.42 seconds.

Move every obstacle toward positive z at the current speed. Slowly rotate obstacles as they move, with rocks rotating slightly faster than trees. Remove them after they pass the player. Detect a collision using horizontal/forward distance: a tree collision radius is about 0.72 and a rock collision radius about 0.65. On collision immediately end the run and show a centered dark translucent rounded “Wipeout!” panel with text such as “You rode [distance] m” and a yellow “Ride again” button. The button resets the course, obstacles, bike, and distance and starts a fresh run. Also provide a bottom-right dark translucent restart button with a circular-arrow icon that can restart the ride.

Use responsive full-screen layout. Overlay UI should use rounded dark blue-gray translucent panels, light text, subtle borders/shadows, and a yellow start/restart action button. Keep the presentation minimal and uncluttered, with the blue sky, green banks, brown trail, snow edges, simple bicycle, trees, and rocks as the only gameplay visuals. On wider screens make the mobile control buttons somewhat translucent so they do not dominate the view; on all screens keep controls usable with touch and keyboard input.