Letter Rail

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 Three.js-style 3D educational toy game titled “Letter Rail.” Show a long alphabet train made from a locomotive plus 26 connected wagon cars arranged in a straight line along an x-axis, one wagon for each letter A through Z. Use colorful low-poly Kenney-style train assets: a locomotive at the beginning and wagon/container variants cycling through blue, green, red, and box styles. Each wagon should carry a large freestanding extruded 3D capital letter, not a badge or sign: render the wagon’s letter in matching bright varied colors, with a visible letter on both sides of the wagon and a smaller letter lying/rendered on top. Letters should be bold, rounded/beveled, highly readable, cast soft shadows, and have a subtle glossy toy-plastic appearance. The train sits on two dark metal rails with regularly spaced brown wooden sleepers over a tan track bed/path, surrounded by a broad soft-green grassy ground plane. Use a bright pale-blue sky background with light fog, distant rounded green hills, and a few simple puffy white clouds. Light the scene with soft sky/hemisphere lighting and a warm directional sun; enable soft shadows. Use a close elevated three-quarter follow-camera view, approximately above and in front of the track, looking toward the currently selected wagon so the selected letter and its colorful car dominate the view while adjacent train cars extend away into the scene. The camera should smoothly pan/follow along the train as the selected wagon changes, and allow a small horizontal drag on the 3D scene to adjust the viewing angle. Keep the visual style bright, friendly, toy-like, and low-poly, with large readable objects and no combat or hazards.

Core interaction: start focused on wagon A with the HUD reading “Letter A.” The player can select the previous/next alphabet wagon with Left/Right arrow keys or the on-screen left/right buttons. Selection wraps from A to Z and Z to A. Selecting a wagon stops automatic rolling, smoothly moves the camera focus to that wagon, and briefly pulses/enlarges all three copies of the selected letter before settling. The selected wagon/letter is slightly larger and bobs subtly; all letters have a gentle continuous vertical bob animation. Space toggles automatic play/pause. When automatic play is active, advance the camera focus continuously through the train from A toward Z at a slow steady speed, update the focused letter as each wagon is reached, pulse the newly focused letter, and wrap back to A after the final wagon. Automatic play does not need to visibly translate the train models; it is a guided camera/focus tour of the stationary alphabet train.

Overlay a fixed responsive HUD above the canvas. At the top center, place a wide dark navy translucent rounded rectangular bar with a thin light border and soft shadow. On its left show the current readout “Letter X” in large bold text, colored to match that letter’s wagon/letter color. On its right show the instructions “← → or buttons: move wagon” and “Space: play / pause” in white. At the bottom center place three large rounded white controls with dark blue text/icons: a left triangle button, a central button labeled “Pause” while auto-play is active or “Play” while paused, and a right triangle button. Buttons should have strong soft drop shadows and a pressed-down visual state, and work with mouse/touch. The scene should fill the viewport, support mobile portrait screens, prevent page scrolling, and keep the HUD readable over the sky. Include a brief dark rounded “Loading alphabet train...” overlay while external train models/font assets load, then hide it when ready. Expose optional game state methods equivalent to getGameState (focused index/letter, autoplay state, loading status, camera position, wagon count/spacing) and setGameState (jump to focused index or toggle autoplay).