Muscle 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 mobile-first 3D endless highway runner titled “Muscle Run.” Use a third-person chase camera behind and slightly above the player car, looking forward down a bright daytime road. The scene should be built in a stylized chunky 3D aesthetic: an unbranded, Dodge-inspired muscle car for the player, boxy aggressive traffic vehicles with broad bodies, stripes, dark roofs or pickup beds, chunky black wheels, headlights, grilles, and red rear light bars. Traffic must consist only of similarly stylized muscle cars and pickup trucks, with varied paint colors such as red/white, black/orange, white/red, navy/yellow, and purple/white; do not use logos or branding.

The road is a repeating straight dark-gray asphalt highway, approximately three lanes wide, with two pale dashed lane dividers and broad muted-green shoulders. Place simple low-poly trees along both sides, plus a blue sky, soft white clouds, atmospheric fog, and strong sunny lighting with soft shadows. The player car begins in the center lane near the bottom of the view. The three lane centers are clearly separated and allow instantaneous input-driven lane changes with smooth lateral motion. The camera subtly follows the player’s lateral position and speed while remaining in a stable chase view.

Implement an endless forward-driving loop: the player remains around the same depth while road segments, trees, and traffic move toward the camera. Spawn traffic vehicles far ahead in a random one of the three lanes. Traffic approaches at speeds below the player’s normal pace; cars and trucks should vary in length, and pickups should be recognizable by their rear cargo bed. Remove vehicles after they pass behind the player. Increase spawn frequency as speed rises. Detect a collision when traffic is in the same lane and close in depth to the player; one collision immediately ends the run.

The player has a continuously managed speed. Start around 24 mph, allow a normal range of about 18–42 mph, smoothly accelerate toward a higher target while holding Gas, smoothly decelerate toward a lower target while holding Brake, and gently return toward approximately 26 mph when neither pedal is held. Distance is the score and increases based on speed; display whole meters. Persist the best distance score locally between runs. On collision, stop the run and show a crash/restart panel with the completed distance, best run, and a brief tip about building speed on clear stretches and braking when traffic stacks up.

Controls must be optimized for thumbs: fixed HUD buttons at the bottom with left and right arrow buttons on the lower left, and tall Brake and Gas buttons on the lower right. Holding Gas or Brake affects speed; tapping left/right shifts one lane, clamped to the leftmost or rightmost lane. Also support keyboard fallback: A/D or left/right arrows for lane changes, W/S or up/down arrows for gas/brake, and Space to start or restart. Any control input should be able to start an idle run, while the prominent Start Run button starts from the intro screen.

Use a dark translucent glass-like HUD over the game. At the top, show two rounded stat cards: Distance with a large meter value and a smaller “Best N m” line on the left; Speed with a large mph value and a smaller lane label (“Left lane,” “Center lane,” or “Right lane”) on the right. Use white text, muted blue-gray secondary text, and warm orange/yellow accents. Before play, display a centered dark translucent modal card over the highway with the eyebrow “MOBILE HIGHWAY RUNNER,” title “Muscle Run,” explanatory copy about switching lanes through unbranded muscle cars and trucks, three bullet tips for lane buttons, Gas/Brake speed control, and avoiding every vehicle, an orange “Start Run” button, and the badge “CARS + TRUCKS ONLY.” On game over, replace it with a similarly styled “RUN OVER / Crash!” modal, distance and best results, restart button, and “Muscle cars + trucks” badge. Keep the viewport full-screen, responsive, touch-friendly, and prevent page scrolling.