Beatbound 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 endless rhythm runner titled “Beatbound Runner,” implemented as a full-viewport HTML canvas game with a fixed HUD layered over it. Use a dark neon arcade aesthetic: a vertical gradient background from deep navy (#0a0b24) at the top to dark purple (#201033) at the bottom, a subtle cyan glowing pulse/orb in the upper-right area, perspective-style cyan grid lines converging toward the horizon, and a dark blue-purple ground section occupying the lower roughly 24% of the screen. Draw a bright cyan horizontal ground line at the top of the ground. Use simple glowing geometric shapes rather than character art.

The player is an approximately 30x42 pixel hot-pink glowing rectangular runner positioned at 22% of the screen width, standing on the ground line. Give it two small white square eyes. It automatically remains in place horizontally while obstacles move from right to left. The player can jump vertically with gravity: jump velocity about -690, gravity about 1800, and return to the ground line; add a brief squash/stretch effect on takeoff/landing. Draw a small particle burst on takeoff, with cyan particles for a perfectly timed jump and pink particles for an ordinary jump, plus a few white landing particles.

Make the core mechanic rhythm-based jumping. Set the beat to 112 BPM (one beat is 60/112 seconds), maintain a repeating beat clock, and play a simple synthesized metronome when the run starts: a low 110 Hz tone on the first beat of each four-beat group, 220 Hz on other beats, and an additional short 440 Hz triangle tone on beats 2 and 4. The player may jump only while grounded. Allow jumping via the large on-screen circular “JUMP” pad at bottom-right, Space, ArrowUp, or tapping/clicking the canvas while running. If the game is not running, a jump input starts a new run; if the run is over, it restarts it. A jump is “perfect” when input occurs within roughly the first or last 14% of the current beat interval (distance from the nearest beat boundary less than 0.14 beat). Perfect jumps increase the combo by one; non-perfect jumps reduce combo by one but not below zero. Award 25 plus three times the new combo for a perfect jump, or 8 for a normal jump. Count perfect jumps and track the best combo.

Spawn simple rectangular obstacles from the right edge after an initial delay of about 1.9–2.2 seconds, then approximately every 2 or 3 beats (randomly, with 22% chance of two beats and otherwise three). Obstacles should have random width around 30–52 pixels, height around 34–69 pixels, and a cyan-to-magenta range of neon hues; draw them as glowing solid rectangles rising from the ground line. Move them left at about 330 pixels/second, increasing slightly with score, and award 10 points when each obstacle fully passes the player. End the run immediately if a rectangle overlaps the player horizontally and reaches the player’s vertical body while the player is not high enough to clear it. Remove obstacles after they leave the screen. The game is endless until collision.

At the top-left, show the uppercase brand “BEATBOUND RUNNER” in bold, spaced lettering. At the top-right show a large white numeric score, initially 0, and a smaller status label. Before play, the status reads “READY.” During play, show “SYNC” initially, then “PERFECT ×N” after a perfect jump or “JUMP” after an ordinary jump. At the bottom center, show uppercase text “SYNC TO THE PULSE” and a narrow rounded beat-progress bar beneath it, with a cyan-to-pink gradient fill advancing across each beat and resetting at the beat boundary. At bottom-right, show a 100x100 pixel round translucent pink jump button with a pink border and bold “JUMP” label.

On initial load, place a centered translucent dark glass instruction card with rounded corners and a subtle border/shadow. It should say “Jump on the beat,” explain “Tap the jump pad or press Space as the pulse reaches the line. Land cleanly to build your combo.”, and include a bright pink pill-shaped “Start run” button. Starting resets elapsed time, beat timing, score, combo, best combo, perfect count, player state, particles, and obstacles, hides the card, and starts/resumes audio. On collision, stop gameplay and show a centered card reading “Run ended,” then display the final Score, Best combo, and Perfect jumps values and a pink “Run it back” button. Keep the game responsive to viewport resizing and preserve touch-friendly controls; use system sans-serif typography, dark background, white text, hot pink (#ff3d9a), and cyan (#44d9ff) accents.