Glow Serpent

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 responsive 2D arcade Snake game titled “Glow Serpent.” Use a full-screen dark canvas with a centered square 24-by-24 playfield. The playfield should scale to fit the viewport, leaving room for the HUD (cell size based on the smaller of available width and height); draw a thin bright cyan border and a subtle cyan grid over a nearly black navy translucent interior. Behind it, render a very dark navy/black radial-gradient background with a slightly brighter blue center.

The player controls a glowing segmented serpent on the grid. At the beginning of every run, place three segments horizontally at the center, with the head at grid coordinate (12,12), followed by (11,12) and (10,12), moving right. Render the head as a bright white square with a strong cyan-white glow; render the body as inset square segments with cyan/teal glow and a cyan-to-light gradient across the body. Place one collectible spark at a random unoccupied grid cell. The spark is a small vivid pink/magenta glowing circle, with a subtle pulsing radius animation.

The core goal is to eat sparks, grow longer, increase score, and survive the accelerating movement. Move one grid cell per game step. Each spark eaten adds 10 points, increases the serpent length by one, and spawns another spark at a random cell not occupied by the serpent. Start with a 155 ms step interval (display speed as 1.0x). After growth, make the interval faster using approximately max(58, 155 - (length - 3) * 4.1), and display the multiplier as 155 divided by the current interval, formatted to one decimal followed by “x.” End the run immediately if the head leaves the 24-by-24 board or collides with any serpent segment. Do not allow an immediate 180-degree reversal. The serpent should continue moving automatically after a direction is chosen.

Support keyboard controls with Arrow keys and W/A/S/D. Support touch/mobile control with a visible four-button directional D-pad on coarse-pointer devices, using up/left/down/right arrow glyphs, and also support swipe gestures on the canvas (horizontal or vertical swipe chooses the corresponding direction). Prevent touch scrolling while interacting with the canvas and controls. Ignore direction input before a run starts, and allow Space to start when the game is not running.

Overlay a HUD above the canvas. In the upper left show the uppercase brand “GLOW SERPENT” in pale cyan/white, heavy weight, wide letter spacing, and cyan glow. In the upper right show three compact rounded dark translucent stat cards with cyan borders/glows labeled SCORE, LENGTH, and SPEED, displaying the current score, serpent length, and speed multiplier. The initial values are 0, 3, and 1.0x. Make the HUD responsive so cards become slightly narrower on small screens.

Before the first run, show a centered overlay over the playfield containing the large uppercase glowing title “GLOW SERPENT,” the subtitle “Eat the sparks. Grow longer. Survive the acceleration.”, and a cyan outlined rounded button labeled “START RUN.” Center this content slightly above the middle. Starting resets score, length, speed, direction, and serpent position, hides the overlay, and begins the run. On collision or wall impact, stop movement and show a centered “RUN OVER” overlay with “Score [score] · Best [best]” and a “RUN AGAIN” button. Persist the best score in local storage under the key glowSerpentBest and update it when a run ends.

Use a polished neon cyber-grid aesthetic: dark navy background, cyan grid and borders, white/cyan serpent, and magenta food. Use canvas glow effects/shadows for the serpent and spark, but keep the gameplay strictly grid-based and 2D. The game should render continuously with requestAnimationFrame and use a time accumulator so movement remains consistent across frames and resizing. Ensure the canvas is full-screen and responsive, while the actual 24-by-24 board remains square and centered.