Neon Rhythm 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 browser-based 2D arcade rhythm endless runner titled “Neon Rhythm Runner.” Use a responsive centered layout on a very dark page with a large red/pink glowing title, the instruction “Press SPACE, tap, or click to jump on the beat.”, a rounded neon-pink framed gameplay canvas, and three small bottom pills reading “120 BPM beat,” “Space / tap to jump,” and “Restart after crash.” The game canvas should be 960x540 internally and displayed responsively at a 16:9 aspect ratio.

Gameplay is side-on and entirely contained in the canvas. The player is a glowing cyan/turquoise square, 42x42 pixels, fixed horizontally around x=120 and standing on a ground line at y=406; it jumps vertically with gravity when the player presses Space, taps, or clicks. Only allow a jump while grounded; use an immediate upward velocity around -14 and gravity around 0.62, with landing clamped to the ground. Add a subtle 2-pixel idle bob while grounded, a pale cyan outline, strong cyan glow, and small cyan particle bursts on jump plus a short particle trail while airborne.

Make the game run to a 120 BPM rhythm: one beat every 0.5 seconds. On each beat play a synthesized kick on alternating beats, a triangle-like snare on the other beats, and a quiet sawtooth bass note cycling through approximately 110, 110, 130.81, and 98 Hz. Start/resume browser audio from the first user interaction. Visually, each beat should create a brief whole-screen cyan pulse and spawn a vertical cyan beat marker entering from the right, moving leftward through a lane from about 90 pixels above the ground to 40 pixels below it, fading as it travels.

Spawn hazards as the run progresses on selected even beats after the first two beats, with some randomness and a cooldown so they are spaced apart. Each hazard is a small glowing hot-pink/red triangular spike, about 28 pixels wide and 36 pixels tall, moving from the right edge toward the player. Move hazards left at an initial speed of 7 pixels per frame-equivalent and gradually increase speed based on score, capped around 13. Detect rectangular overlap between the square player and spikes; on collision set the game to over, preserve/update the best score, and burst red particles around the player. Remove spikes after they leave the left side.

While alive, continuously increase the score approximately one point per frame at 60 FPS, and show a monospace HUD inside the canvas: “SCORE [number]” at the upper left, “BEST [number]” below it, and “BPM 120” at the upper right in cyan. Before the first interaction, show centered cyan text “TAP OR PRESS SPACE” and white text beneath it “Jump with the beat to clear spikes.” A first Space/tap/click starts the run and initializes the beat scheduler; subsequent input jumps. After a collision, show centered hot-pink “CRASHED!” and white “Tap or press Space to restart”; any Space/tap/click resets score, speed, obstacles, particles, player position, and beat timing and begins again.

Use a neon synthwave visual style. The canvas background is a vertical gradient from deep navy/purple (#0d0221) at the top through dark violet (#261447) to hot pink/red (#ff3864) at the bottom, with a faint cyan beat pulse overlay and subtle translucent vertical grid lines every 60 pixels. Draw a glowing gold ground line at y=406 with a dim perspective-like moving diagonal streak pattern beneath/around it. Render beat markers, cyan player, red spikes, and particles with canvas shadows/glows. The outer page should use a dark radial-gradient background, Segoe UI/Roboto-like typography, a high-letter-spacing pink title, rounded 18px pink border around the game, pink outer glow and faint cyan inset glow. Do not add weapons, enemies beyond the triangular spikes, powerups, multiple lanes, lives, or other mechanics not described.