Cube Rush

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 browser-playable 3D endless runner titled “Cube Rush,” using Three.js with a PerspectiveCamera. Show a fixed side-on/three-quarter view of a neon rectangular lane extending into the distance horizontally, with the camera around (0, 4.6, 10.5) looking toward the player and lane. The world should have a dark navy background and fog, sparse small white stars in the open sky, a wide dark-blue raised ground block, two darker ambient strips, and repeating bright cyan lane/grid lines that scroll backward to communicate motion. Use soft shadows, an overhead directional light, and a cool neon arcade/Geometry Dash-inspired visual style without copied assets.

The player is a simple bright yellow-orange glowing cube, about 1.2 units on each side, with two small dark square eyes on its front face. It automatically runs to the right while remaining near the left side of the screen; the environment, obstacles, and portals move from right to left. While airborne, rotate the cube around its Z axis, and show a brief trail made from small glowing green cube particles after jumps and portal activations. The cube starts on the ground and has gravity-based jumping physics: a jump velocity of 13.8, gravity of 34, and only one jump when grounded. Accept Space, W, Up Arrow, mouse click, a tap anywhere, or the on-screen JUMP button. Ignore jump input before starting, after crashing, while paused, or while already airborne.

The primary goal is to survive as long as possible by jumping over incoming hazards. Spawn ordinary spike obstacles after the run begins, initially about every 1.0–1.55 seconds, gradually reducing the interval toward roughly 0.6–0.95 seconds. Obstacles are red/pink glowing low-poly four-sided cone spikes mounted on a dark red rectangular base; most contain one spike, and about 22% contain two adjacent spikes. Every obstacle successfully passed adds 1 to SCORE. The run speed begins at 9 world units per second and continuously ramps by 0.35 per second, normally capped at 18. Collision between the cube’s approximate box hitbox and a spike or other obstacle ends the run immediately.

After the first four seconds, periodically create authored portal sections rather than dropping unrelated random portals. Use this repeating section order: HIGH gravity, LOW gravity, MINI, FAST speed, then REV reverse, repeating. Each section begins with a large glowing torus portal centered around y=2.2, with two thin vertical side beams, a translucent circular core, and a small bordered label beneath it reading HIGH, LOW, MINI, FAST, or REV. Portals rotate around their Z axis, flash/pulse when activated, expand and fade after activation, and use distinct colors: HIGH cyan, LOW orange, MINI violet, FAST pink/red, and REV white/green. Place matching hazards after each portal in fixed patterns:
- HIGH: single spikes at offsets 4.4, 8.8, and 13.8, then a pair at 18.8; this mode makes jumps higher by using gravity multiplier 0.82 and jump velocity 1.18x.
- LOW: single spikes at offsets 3.1, 5.4, and 7.9, then a pair at 10.9; this mode makes jumps lower with gravity multiplier 1.18 and jump velocity 0.82x.
- MINI: low-ceiling gate obstacles at offsets 3.8, 7.1, and 13.4, plus a single spike at 10.3. Each gate is a purple horizontal beam around y=2.05–2.18 with two narrow posts, forcing careful low-jump timing. Toggle the cube to approximately 62% scale while MINI is active.
- FAST: single spikes at offsets 4.2, 7.1, and 13.2, with pairs at 10.0 and 16.1; increase speed immediately by about 5.2 and run a 4.5-second burst, with a maximum of 23.
- REV: pairs at offsets 3.5 and 9.8, and single spikes at 6.7 and 13.6; toggle an inverted-looking palette using color inversion/remapping, advance the theme, and produce a stronger white/green flash and screen pulse.

Portal activation itself awards bonus score: HIGH, LOW, and MINI award 2 points, FAST awards 3, and REV awards 4. Section hazards still award 1 point each when passed. Do not spawn ordinary random obstacles while an authored portal section is active. After its portal and all matching hazards leave the screen, wait roughly 6.8–9.6 seconds before starting the next section. Portal sections should preview their matching obstacle sequence clearly.

Cycle the overall color theme as portal modes are encountered. The initial palette is navy/blue ground and cyan lines, with yellow-orange player and green trail. Additional palettes include a purple/pink environment with cyan player and pink lines, and a green/teal environment with yellow player and green lines. HIGH/LOW change theme, REV changes theme and toggles the inverted palette; apply the palette to background, fog, ground, strips, grid lines, cube, trail, lights, and portal materials. Show a radial full-screen pulse overlay on portal activation, colored to match the effect, and briefly intensify the cube/trail emissive glow. Slightly pulse camera height and move the camera closer during strong pulses.

Build a fixed mobile-friendly HUD over the canvas: top-left translucent dark panel with bold text “SCORE 0” (updating as points are earned), top-right translucent hint reading “Tap, click, or press Space to jump” on larger screens, and a square translucent cyan JUMP button at bottom-right. On the initial screen, center a translucent dark overlay card with a thin light border, the title “CUBE RUSH,” the text “A Geometry Dash-style runner. Jump over spikes and survive as the speed climbs.” and a bright green START button. Clicking/tapping START begins a fresh run, resets score, speed, player, theme, modifiers, obstacles, portals, and section sequence. On collision, stop gameplay and show the centered overlay with title “Crashed,” text “Score [score]. Best [best]. Tap restart and try again.” and a green RESTART button. Pressing R after a crash also restarts. Keep the HUD responsive for mobile safe areas, hide the hint on narrow screens, prevent page scrolling during touch controls, and make the overall presentation clean, blocky, bright, and arcade-like.