Fossil Run

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 playable browser-based 3D endless survival runner titled “Fossil Run,” using a low-poly Three.js-style aesthetic. Use a third-person chase camera positioned behind and above the player, looking forward down a three-lane prehistoric valley. The scene should have a pale green sky/background with distance fog, warm directional sunlight, soft shadows, and a broad repeating green grass roadway/valley floor bordered by darker green ground. Place simple low-poly conifer-like trees with brown trunks and layered dark-green cone foliage along both sides; recycle the ground segments and trees so the world appears to move endlessly toward the camera.

The player is an auto-running, low-poly beige/tan explorer-like character centered near the bottom of the view, with a rounded capsule body, spherical head, dark brown rectangular backpack, and two dark brown blocky legs. The player continuously advances forward automatically while the environment, obstacles, collectibles, and scenery move toward the player. There are exactly three lanes, at x positions left, center, and right. Press A or Left Arrow to shift one lane left, and D or Right Arrow to shift one lane right; smoothly interpolate the character between lanes and prevent moving beyond the outer lanes. Press Space to jump. The player should have gravity, a short visible jump arc, and alternating leg motion/bobbing while running; jumping allows the player to clear low obstacles. Press P to pause and resume.

Spawn hazards ahead in random lanes and move them toward the player: alternating low-poly gray-brown dodecahedral rocks and horizontal brown logs. Rocks sit slightly higher and logs are rotated sideways across their lane. Detect collisions when the player and obstacle are in the same lane/nearby x and z position while the player is low enough; a sufficiently high jump avoids them. On collision, remove the obstacle, subtract one life, subtract 40 score without going below zero, briefly flash the player reddish, play a hit sound if audio is available, and reduce running speed slightly (but do not below 12). Start with 3 lives. Spawn glowing orange-gold faceted amber octahedrons in random lanes at varied heights, spinning as they approach. Collecting one removes it, increases the amber counter by 1, adds 25 score, and plays a short bright pickup sound.

The run score should steadily increase with time/distance, while amber adds bonus score. Begin at speed 16 and gradually ramp speed over time, capped at 28; slowly increase the difficulty by shortening spawn intervals as the distance level rises. Keep a blocky low-poly T-Rex visibly chasing behind the runner: a dark brown simplified dinosaur made from boxy body, head, long tail, two legs, and small arms. It should follow the player’s lateral position and remain behind, but move closer as lives are lost and as the level rises. When lives reach zero, end the run with the T-Rex catching the player, stop gameplay, and show a centered dark translucent overlay reading “T-REX GOT YOU” plus the final score and “Press Space to run again.” Pressing Space after game over resets score, amber, lives, speed, distance, player position, T-Rex position, and all active obstacles/pickups, then starts a new run. While paused, stop world updates and show a centered “PAUSED” overlay.

Add an always-visible HUD over the canvas in the upper-left with four dark translucent green rectangular panels labeled SCORE, AMBER, LIVES, and SPEED, showing their current numeric values (initially 0, 0, 3, and the running speed). In the upper-right, show a dark translucent help panel titled “FOSSIL RUN” with the text “Dodge rocks and logs. Grab amber. Don’t get eaten.” and the control hint “A/D or ←/→ move — Space jump — P pause.” On narrow screens, wrap the HUD and move the help panel to a bottom full-width panel. Use clean sans-serif typography, pale cream text, muted green labels, and a dark translucent overlay for pause/game-over states. Include simple Tone.js-style synth feedback for jump, amber pickup, and hit, initialized after user interaction, but keep the game fully playable without audio.