Subway Girl

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 3D third-person endless runner titled “Subway Girl.” The game takes place in a dark underground subway tunnel viewed from behind and slightly above the player, with a perspective camera following her as she runs forward down the tunnel. The player is a casual-looking 3D female character running automatically toward the far end of the tunnel; use a visible looping run animation while playing and a death/crash animation after hitting an obstacle. Keep her on one of three fixed lanes, approximately left, center, and right, with smooth horizontal movement between lanes. The tunnel should be a long repeating environment: a broad dark gray floor with three pairs of metallic rails (one pair per lane), thin yellow lane-divider stripes, purple-gray side walls and support pillars, a dark ceiling, and regularly spaced warm rectangular ceiling lights that cast a soft glow. Use a dark navy/purple background and atmospheric fog so the tunnel fades into darkness in the distance. The overall visual style is polished, low-poly/stylized 3D with warm light accents and pink/orange UI accents.

The character continuously advances through a sequence of recycled tunnel sections, with a clear empty starting section and procedurally varied content farther ahead. Place content at several positions along the tunnel: tall subway trains occupying a lane, and low pink/magenta rectangular barriers that must be jumped over. Trains are tall obstacles that cannot be cleared by jumping; the player must switch to another lane. Barriers are low enough to clear with a jump. Sometimes two neighboring lanes can be blocked, but leave a navigable lane. Also place collectible gold star/coin objects in lanes: individual coins, short lines of two or three coins, three-coin arcs, and coins positioned above barriers or in an otherwise free lane. Coins should visibly rotate while they wait to be collected and disappear when picked up.

Controls: Left Arrow or A moves one lane left; Right Arrow or D moves one lane right; Space, Up Arrow, or the on-screen up button jumps. Lane changes are discrete among the three lanes, with smooth visual interpolation. Jumping uses gravity and a single jump at a time; the player starts on the ground, rises, then lands automatically. On touch devices, show three translucent circular controls along the bottom: left arrow on the lower left, right arrow beside it, and an up-arrow jump button on the lower right. Also support swiping on the play area: horizontal swipes switch lanes and an upward swipe jumps. Prevent movement outside the left and right lanes.

The run begins from a full-screen start overlay. Use a nearly black/navy radial-gradient overlay with centered text: a large uppercase “SUBWAY GIRL” title in a pink-to-orange gradient, the description “Dash through the underground tunnels. Switch lanes, leap barriers, dodge trains, grab the coins.”, a rounded bright pink “START RUN” button, and the hint “← → switch lanes · SPACE / ↑ jump.” Clicking/tapping the button, pressing Space before starting, or tapping the play area starts the run. Hide the start overlay during play.

During play, display a minimal HUD at the upper left: a large white numeric score and below it a gold star symbol followed by the coin count. Score is based on forward distance plus five points per collected coin; show integer values. The automatic run speed starts at a moderate pace and gradually increases over time to a capped maximum, making later sections more difficult. The player travels forward continuously while the tunnel sections and their obstacles are recycled behind/far ahead to create an effectively endless course.

Collision rules: a train causes an immediate crash when the player is in its lane and at its depth, even if jumping high (jumping does not help against trains). A low barrier causes a crash only if the player is in its lane and has not risen high enough; jumping above roughly the barrier height clears it. Coins are collected only when the player is close in lane, depth, and vertical position. On a crash, stop the run, play a brief camera shake and crash sound, show the character’s death animation, then display a centered game-over overlay with the heading “CRASHED,” the final numeric score in gold, the label “meters,” and a rounded pink “RUN AGAIN” button. Pressing Space or clicking/tapping the button resets the run, score, coins, player position/lane, tunnel content, and speed and starts again. Add simple arcade audio feedback: a two-tone chime for coins, a short rising tone for jumping, and a low two-part crash sound. Use soft shadows, warm ceiling lighting, fog, and subtle camera shake on impact.