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 game titled “Rhythm Runner,” presented in Spanish with a polished dark neon arcade style. The game should have a menu overlay centered over a full-screen canvas. Use a nearly black/navy background and a rounded translucent navy panel with thin blue border and shadow. The title reads “RHYTHM RUNNER,” with “RHYTHM” in white and “RUNNER” in mint/turquoise, followed by the subtitle “Corre al pulso. Completa la letra. No pierdas el ritmo.”

Menu features: a YouTube URL input labeled “Enlace de YouTube,” a “Comprobar enlace” button, and a status message initially saying “Modo demo listo: puedes jugar con una pista de prueba.” Validate youtube.com/watch?v=... and youtu.be/... links, showing an invalid-link message for other text and a success message that the official playback is ready to integrate without downloading audio. Do not actually download or play YouTube audio. Include a multiline textarea labeled “Letra sincronizada — una línea por fragmento,” prefilled with four English lyric lines: “Run with the rhythm tonight”, “Jump when the bright lights glow”, “Keep your focus, don't slow down”, and “Answer right and steal the show”. If fewer than four nonempty lines are entered, fall back to those four demo lines. Include three difficulty buttons: “Fácil” selected by default, “Normal,” and “Difícil.” Include a sound toggle reading “Sonido: activado” / “Sonido: silenciado,” and a large gradient mint-to-blue “Iniciar partida” button. Explain controls in a small hint: tap SALTAR or press Space; obstacles and lyric questions are part of the run; the YouTube link is only validated for this web version.

Core gameplay is a 2D side-scrolling endless-runner-like timed course rendered on a full-screen HTML canvas. The player stays near x=120 while the world scrolls left. The scene has a vertical navy gradient sky fading from approximately #161d4f to #090b19, sparse glowing blue star/dot decorations, and a dark navy ground beginning around 78% of the screen height. The ground has a blue top edge and repeating short mint lane markings. Use a small pink duck platformer sprite if available (the implementation uses a Kenney pink duck character image); otherwise render a simple mint player block. The character is approximately 42x54 pixels, stands on the ground, and can jump with an upward impulse and gravity. Controls are Space, ArrowUp, or the large round ↑ touch button at the bottom-right. Only one jump is allowed while airborne.

Spawn pink glowing rectangular obstacles from the right and move them left at the selected difficulty speed. Most are short blocks around 48x38, with occasional taller blocks around 34x78; add a small gold highlight stripe near the top of each. Collision with an obstacle increments Errores, subtracts 50 points (never below zero), flashes pink particles, and plays a low synthesized blip if sound is enabled. Spawn gold coin collectibles intermittently above the ground, usually ahead of an obstacle; collecting one adds 50 points, flashes gold particles, and plays a higher blip. Coins may use a Kenney gold coin sprite or a simple gold circular fallback.

Difficulty must affect actual mechanics: Fácil uses speed 260, obstacle spawn gap behavior around 520, lyric question interval 11, and jump impulse 640; Normal uses speed 320, gap around 420, question interval 8, and jump impulse 680; Difícil uses speed 390, gap around 340, question interval 5, and jump impulse 720. Obstacles should spawn probabilistically as the run progresses. The run lasts 32 seconds unless interrupted by a lyric question. Display a top HUD during play with rounded pills for “Puntos 0,” “Errores 0,” and the selected difficulty, plus a “Pausa” button. The pause button changes to “Reanudar” and freezes the simulation; resuming continues from the same state. Below the HUD, show a centered rounded lyric bar with a small song label (“Demo de Rhythm Runner,” or “YouTube · [validated id]” after successful validation) and the current lyric line, cycling through the supplied lines approximately every two seconds. At the bottom, show the hint “Salta obstáculos y responde la letra” and the round ↑ jump control.

At recurring distance thresholds, pause the scrolling game and show a dimmed full-screen modal. Ask “¿Qué parte de la canción sigue?” and show the current lyric in quotation marks. Generate four answer buttons in a two-column grid (one column on narrow screens), with the correct answer being the next lyric line cyclically and three other lyric choices/random options from the supplied lyrics. A correct answer adds 250 points, resumes play, and produces a positive high-pitched blip. A wrong answer increments Errores, subtracts 100 points without going below zero, resets elapsed run time/distance and clears obstacles and coins, resets the player to the ground, resumes play, and emits a pink damage particle flash with a low blip. Questions must genuinely pause movement until answered.

When 32 seconds of active running is reached, stop the game and show a centered result modal over the final canvas. Use the text “Recorrido completado,” “¡GANASTE!,” a large mint final score, and a summary in the form “Errores: [count] · Dificultad: [label] · Canción: [enlace de YouTube validado or Demo de Rhythm Runner]”. Provide “Jugar de nuevo” and “Menú principal” buttons. Replay resets score, errors, time, distance, player, obstacles, coins, and lyrics while retaining the chosen difficulty and entered lyrics. Returning to the menu hides gameplay HUD and restores the setup panel.

Use responsive layout: the menu is about 560px wide or 92vw, vertically centered, scrollable if needed, with rounded 22px corners; on small screens reduce padding/title size and stack answer buttons into one column. Use the visual palette: background #090b19, panel #121732 with transparency, white text, muted lavender-blue labels, mint #64f3c2, pink #ff5da2/#ff5d8f for hazards, and gold #ffd166. Add subtle glow/shadow effects, rounded buttons, gradient primary buttons, and brief square particle bursts for jumps/collectibles/damage. Optional sound consists only of short Web Audio triangle oscillator blips controlled by the sound toggle.