Pulse Snake

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 browser game titled “Pulse Snake,” a neon cyberpunk version of classic grid Snake. Use a full-viewport dark canvas with background color near-black navy (#050611), centered in the page and no scrolling. Draw a square-cell playfield whose cell size adapts to the viewport: approximately 20 columns/rows on desktop, with a minimum of 12 columns and 12 rows; keep the board centered, with a small downward offset. Render a faint cyan grid over the board and a soft radial colored glow around its center. The visual style is minimalist, futuristic, and arcade-like, with cyan and magenta bloom/glow effects.

At launch, show the game idle with a centered message overlay around 43% down the screen. Display a large two-line glowing white/magenta/cyan title “PULSE SNAKE,” followed by the text “Eat the cyan sparks. Every spark makes you longer — and faster.” and a pill-shaped neon magenta button labeled “START RUN.” The top HUD remains visible: “SCORE” at upper left with a large 0 beneath it, and “LENGTH” at upper right with a large 3 beneath it. Use uppercase labels, wide letter spacing, white/cyan text, and cyan text-shadow. At the bottom center, show a four-button directional pad arranged as up above, left/down/right below; buttons are circular-ish neon cyan outlined controls with translucent cyan fills and arrow glyphs. Make these controls usable for touch/pointer input; on wider screens they can appear somewhat dimmed.

When Start Run is clicked, reset the snake and hide the message overlay. Place a three-segment snake at the center of the grid, oriented horizontally with its head on the right and initially moving right. The snake moves continuously one grid cell at a time at an initial speed of 7 steps per second. Draw each segment as a small rounded square centered in its cell, with vivid cyan-to-hue-shifting coloration and glowing shadows; the head should have the strongest glow. Place one glowing cyan circular spark (food) at a random unoccupied grid cell. Animate the spark’s radius subtly with a sine-wave pulse and give it a strong cyan glow.

The player’s goal is to collect sparks. Moving the head into the spark awards 10 points, increases the snake length by one because the tail is not removed on that step, increases movement speed using the formula 7 + snake length * 0.38, capped at 18 steps per second, shifts the snake’s color hue by 28 degrees, and creates a brief brighter board-border pulse. After every collection, spawn the next spark at a random cell that is not occupied by the snake. Update the top HUD score and length immediately. The playfield has solid boundaries: if the head exits the grid, end the run. Also end the run if the head enters any snake segment. Do not allow an immediate 180-degree reversal: ignore a requested direction if it is exactly opposite to the current direction.

Support keyboard controls with Arrow Up/Down/Left/Right and W/A/S/D. Support the on-screen up, down, left, and right buttons through pointer/touch presses. Ignore direction requests while idle or after game over. The Space key should start a run when no run is active. Use a fixed-timestep/accumulator style update so movement remains stable across animation frames, while rendering continuously with requestAnimationFrame.

During an active run, draw a thin glowing outline just outside the board, with its opacity briefly increased after collecting a spark. Keep the faint grid visible behind the snake. The background glow should use the current snake hue and gradually shift as sparks are collected. Preserve the best score in browser local storage under a key equivalent to “pulseSnakeBest.”

On collision, stop movement and show the centered overlay again. Change the title to “SIGNAL LOST,” change the subtitle to `Score [current score]  •  Best [best score]  •  The grid is hungry for a rematch.`, and change the button label to “RUN AGAIN.” Starting again fully resets score, speed, hue, pulse, snake position, direction, and food while retaining the stored best score. The final experience should remain purely 2D canvas rendering with HTML/CSS HUD and controls, responsive to device pixel ratio, and should not add obstacles, enemies, lives, weapons, or other mechanics not described here.