Pulse Cubes

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 3D rhythm/timing game titled “Pulse Cubes.” Use a dark futuristic neon presentation with a nearly black navy background (#070916), subtle fog, scattered tiny blue-white star particles, and a low-poly/clean Three.js-style scene viewed from a slightly elevated perspective camera. The camera looks down a long four-lane beat track and gently sways horizontally over time. The floor is a dark blue plane with faint transverse grid lines. Four long glowing lane rails run toward the distance, positioned left-to-right at x coordinates corresponding to four evenly spaced lanes; color them cyan, pink, purple, and warm yellow. At the near end of each lane, around the center foreground of the playfield, place a glowing flat circular target ring/pad in the matching lane color.

The core mechanic is one incoming cube at a time in a repeating lane pattern. When play begins, spawn emissive colored cubes far down the track, around z=-18, each assigned to one of the four lanes. They move straight toward the camera/target at about 7.3 world units per second, arriving at the target around z=0. Cubes are roughly 1.05 units on each side, brightly emissive in their lane color, slightly metallic, with roughness, and begin with varied random rotation; continuously rotate as they travel and subtly pulse in size. Spawn cubes initially about every 0.78 seconds, gradually shortening the interval with elapsed time but never below about 0.42 seconds. Use the repeating lane selection pattern based on the beat index (equivalent to lane = (beatIndex*7+3) modulo 4), so the sequence is deterministic but distributed among lanes.

The player must press the matching lane at the moment its cube reaches the glowing circular pad. Support keyboard keys 1, 2, 3, and 4, as well as four large touch/click buttons at the bottom labeled 1, 2, 3, and 4. On a lane press, find the nearest active cube in that lane. If it is within 2.15 units of the target, register a hit; timing quality is PERFECT when distance from z=0 is below 0.55, GREAT below 1.15, otherwise OK. Award 100 points for PERFECT, 65 for GREAT, and 30 for OK, multiplied by (1 + floor(current combo / 8)). Increase combo and update best combo on every successful hit. A successful cube visibly flares and enlarges briefly before being removed. If there is no matching cube in range, show MISS in pink/red and reset the combo. Cubes that pass beyond z=2.3 without being hit also count as MISS and reset the combo. Display temporary feedback such as “PERFECT +100,” “GREAT +65,” “OK +30,” “MISS,” and an initial “READY.”

Each run lasts 45 seconds, then stops and displays a completion overlay with “Beat complete,” the final score, the best combo, and “Tap start to play again.” Starting or restarting resets score, combo, elapsed time, and all active cubes, while preserving the best combo in browser local storage. A spacebar press should also start the game when it is not running. There are no lives, health, ammo, enemies, or additional power-ups.

Build a fixed HTML HUD over the 3D canvas. In the upper-left show the small uppercase brand “PULSE CUBES” with wide letter spacing and a cyan glow. In the upper-right show three translucent dark rounded statistic cards labeled SCORE, COMBO, and BEST with white numeric values, thin blue/cyan borders, and a subtle blurred-glass appearance. At the center upper/middle area before play, show a large glowing “Pulse Cubes” heading, the instruction “Hit the cube when it reaches the glowing ring. Use 1 2 3 4 or the buttons below.” and a pill-shaped gradient cyan-to-purple button labeled “START THE BEAT.” Hide this overlay while playing. Put timing feedback around the lower-middle of the screen. Above the controls, show the small hint “Perfect timing builds your combo.” Along the bottom center, place four wide equal buttons with dark blue translucent backgrounds, rounded corners, white bold numerals, subtle borders, and an active press brightness/translation effect. Make the layout responsive for mobile, with the four buttons fitting across the bottom and HUD cards shrinking slightly on narrow screens. Use only the visual language visible here: deep navy space, soft cyan/purple/pink glows, clean sans-serif typography, rounded glass panels, and restrained neon accents.