Subway Runner

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-friendly 3D endless runner titled “Subway Runner,” using a Three.js-style real-time 3D scene and a dark navy full-screen interface. The game is played from a third-person chase camera behind and slightly above a stylized humanoid runner moving continuously forward along an endless three-lane subway/rail track. The camera should use a perspective view, follow the runner smoothly, sit roughly at the runner’s height plus 5 units and 9 units behind, and look ahead down the track. Use a bright sky-blue background with atmospheric fog fading the distant track and city.

Build the runner as a simple low-poly/cartoon character: turquoise rectangular torso, peach spherical head, dark blue visor across the face, two dark navy legs, and coral/pink arms. Animate slight limb swinging while running. The character can shift horizontally between three lanes at x positions approximately -2.2, 0, and 2.2, interpolating smoothly toward the selected lane. The track is made from repeating sections about 18 units long: a dark slate rectangular rail bed, two long pale rails near the sides, brown sleeper/stripe details, and bright teal curbs/side strips. Add occasional dark teal bridge rails along the outer edges. Place simple industrial city buildings on both sides of the track, varying their positions, scale, and appearance; use boxy industrial-building models or similarly simple structures. Light the scene with soft hemisphere lighting and a strong directional sun, with shadows enabled.

The runner advances automatically, beginning at speed 15 and gradually accelerating up to speed 28. Generate track and gameplay objects ahead of the player continuously, keeping roughly 150 units available. Remove objects far behind the player. Randomly create these hazards and collectibles in the lanes: orange low barriers about 1.65 wide and 0.7 high, which can be avoided by sliding; purple trains about 1.8 wide, 2.4 high, and 4.2 long with a cyan window, which require changing lanes or jumping; and dark blue roadblocks about 1.6 wide and 1.3 high with a yellow warning stripe, which can be avoided by changing lanes or jumping. Spawn patterns should include a single blocked lane with coins in the other lanes, a train in one lane with coins in the alternatives, or lines of five coins across varying lanes. Place rotating/bright gold coin tokens in lanes, generally around 1.2 units above the track. Collecting a coin increments the persistent coin total and awards 25 score points.

Support three movement actions: horizontal lane changes, jumping, and sliding. Keyboard controls are Arrow Left/Right or A/D for lane changes, Arrow Up/W/Space to jump, and Arrow Down/S to slide. Also provide on-screen touch buttons: left and right arrows at the bottom-left, and down/slide and up/jump buttons at the bottom-right. Support swipe gestures on the canvas: horizontal swipes change lanes, upward swipes jump, and downward swipes slide. Lane changes clamp to the three available lanes. A jump launches with vertical velocity about 9.8 and gravity about 24, allowing hazards to be cleared while airborne. Sliding lasts about 0.62 seconds and visually scales the runner vertically to about 62%; sliding specifically avoids low orange barriers. Do not allow jumping unless the runner is on the ground, and do not allow sliding while airborne.

Sometimes spawn glowing faceted power orbs: cyan shield orbs and pink magnet orbs. Collecting a shield grants approximately 7 seconds of protection; the next collision with an obstacle consumes the shield, removes the obstacle, and awards 50 score instead of ending the run. Collecting a magnet grants approximately 8 seconds during which nearby coins within about 5 units move toward the runner and are collected. Powerups should be visually distinct glowing colored icosahedron-like objects.

Collision checking should consider objects near the runner’s forward position and the current lane. Coins and powerups disappear on collection. If the player contacts an obstacle while not jumping and not correctly sliding, end the run unless a shield is active. Score should continuously reflect distance and coins, using approximately score = floor(distance * 2 + totalCoins * 5), while coin pickup immediately contributes its 25-point value until the next continuous score update. Track distance in meters based on forward position.

At the top of the screen during play, show three dark translucent rounded pills labeled SCORE, COINS, and BEST with their numeric values. Save the all-time coin total and best score in local storage so they persist between sessions. Start with a full-screen translucent dark-blue overlay and centered rounded card: large cyan “SUBWAY” over yellow-accented “RUNNER,” the subtitle “Dash the city. Own the track.”, a large yellow PLAY button with a darker pressed/shadow edge, instructions reading “Swipe ◀ ▶ to change lanes · swipe ▲ to jump · swipe ▼ to slide,” and small text “Original endless runner slice · local progress saved.” During play, reveal the HUD, touch controls, and a subtle bottom-center hint reading “Collect coins and stay sharp.”

When the player collides with an unshielded obstacle, show a full-screen game-over overlay with a dark purple-tinted rounded card, the heading “RUN OVER,” a line showing “Score [value] · Distance [value]m,” a yellow “RUN AGAIN” button, and “Best score: [value].” Hide the gameplay controls on this screen. The interface should use rounded cards and buttons, high-contrast white text, cyan borders/highlights, navy backgrounds, and yellow/gold action accents. Ensure the game is genuinely playable, starts from the PLAY button, can restart from RUN AGAIN, and resizes responsively for portrait mobile screens.