Rhythm Shredder

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 rhythm guitar game titled “Rhythm Shredder,” using a dark neon arcade presentation and a simple orthographic 3D/2D-rendered scene. The game’s core playfield is a vertical five-lane note highway centered on screen, with a dark navy-blue translucent rectangular track, subtle vertical lane dividers, a horizontal white hit line near the bottom, and five colored circular fret targets below the hit line. Lanes are ordered left to right: green, red, yellow, blue, orange. Notes are colored circular gems that scroll from the top of the highway toward the hit line according to their scheduled hit timestamps. Normal notes use the lane color; star notes are white/light with a cyan-blue outlined ring. Sustained notes have a narrow colored vertical tail extending behind/above the note head. HOPO notes have a small white indicator dot beneath the note. Keep the surrounding background nearly black/dark blue with minimal visual decoration.

The player selects a song and difficulty from a start menu overlay. Show the large heading “Rhythm Shredder,” the instruction subtitle “Hold frets (A S D F G) — Strum with Space — Star power with P,” a Song dropdown with “Neon Riff” and “Sunset Stride,” a Difficulty dropdown with Easy (3 frets), Medium (4 frets), Hard (5 frets), and Expert (denser), a Fullscreen Toggle button, and a wide Start button. Also show a controls list: frets A/S/D/F/G, strum Space/Enter, star P when the meter is full, hyperspeed H, and pause Esc, plus a note that clicking once enables audio under browser autoplay rules. Use a translucent near-black rounded card with a subtle border and shadow over the playfield.

Gameplay uses keyboard controls: hold A, S, D, F, or G for the corresponding fret lane, then press Space or Enter to strum. Allow multiple held frets to hit eligible simultaneous notes. Judge strums against the nearest playable note in the held lane using timing windows of Perfect within ±25 ms, Good within ±50 ms, Ok within ±100 ms, and Miss outside that range. Display transient feedback near the lower center of the screen such as “Perfect,” “Good,” “Ok,” “Miss,” “Clank,” “Perfect ★,” “STAR POWER!,” “Star ended,” and speed-change messages; successful hits also create a brief expanding/fading ring flash at the hit line in the relevant lane. A strum with no fret held causes a small penalty. Notes that pass the hit window automatically become misses.

Implement HOPO behavior: a note marked HOPO may be hit by pressing its fret without strumming only when it follows a previous Perfect hit on the same lane and is no more than 100 ms after that previous note. Sustains are started by strumming the note and require the matching fret to remain held for the sustain duration; award continuous sustain points while held, and break the streak and slightly reduce the rock meter if the fret is released early.

Use scoring and survival rules matching the game: each successfully hit note starts at 50 base points, modified by quality (Perfect 1.25x, Good 1.0x, Ok 0.85x), then multiplied by the current streak multiplier. Award sustain points at 10 points per second, also multiplied. Streak increments on hits, resets on misses or broken sustains, and the multiplier is 1x at 0–9 streak, 2x at 10–19, 3x at 20–29, and 4x at 30+. Start the Rock meter at 70%; successful notes slightly refill it, misses drain it substantially, and sustained successful holding refills it slowly. End the run with “Failed!” when Rock reaches zero. When the song duration is over, show a completion screen instead.

Star notes fill a Star meter by 25% each. When it reaches 100%, allow P to activate Star Power. Star Power lasts up to 8 seconds, drains the meter over that time, doubles the normal multiplier up to an 8x cap, and displays “STAR POWER” in the star meter hint. Before activation, show “Collect ★ notes,” and when full show “Press P to activate.” The left side of the HUD has a vertical ROCK meter with a green-to-yellow-to-red gradient fill. The right side has a vertical STAR meter with a cyan-to-purple/pink gradient fill. At the top right, show a translucent stats panel with Score, Streak, Mult, Acc, and Speed values, initially Score 0, Streak 0, Mult 1x, Acc 0%, Speed 1.0x. Accuracy is successful judged notes divided by total judged notes.

Support hyperspeed with H, cycling through 1.0x, 1.25x, 1.5x, and 1.75x. This changes the visual lookahead so notes appear closer to the hit line for faster settings, and update the HUD speed label. Support Esc to pause and resume. The pause overlay should say “Paused” and list Esc resume, R restart song, and M back to menu. At the end, show a centered translucent results card with “Song Complete” or “Failed!”, Score, Accuracy, Longest Streak, and a five-star rating from one to five, plus Replay and Menu buttons. Allow R to replay after ending and M to return to the menu.

Include two built-in songs represented by timed note charts. “Neon Riff” is 140 BPM, 42 seconds, with a neon synth preset and notes distributed across all five lanes, including star notes, HOPO sequences, simultaneous notes, and sustains around 6.5 s, 15 s, and 29 s. “Sunset Stride” is 120 BPM, 38 seconds, with a sunset synth preset and a similarly varied chart, including star notes, HOPO runs, and sustains around 5.3 s, 20.5 s, and 28.5 s. Easy filters out lanes above the first three (green/red/yellow), Medium uses four lanes, Hard uses all five, and Expert uses all five while adding denser extra derived notes. The backing audio should be generated with a browser synth system such as Tone.js: use a simple kick/drum pulse, repeating bass pattern, and repeating pad chords; use an E/G/A/B/D-flavored neon progression for Neon Riff and an A/C/D/E/G-flavored sunset progression for Sunset Stride. Audio may require the first click or key press to start, but gameplay must remain functional if audio cannot start. Use responsive layout: on narrow screens hide the side meters, stack the menu controls, and keep the highway and HUD usable.