Starfall Assault

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 portrait-friendly 2D arcade space shooter called "Starfall Assault". Use a full-screen HTML canvas with a dark vertical gradient background, from near-black navy at the top (#050816) to deep blue-purple at the bottom (#10113c), and a sparse scrolling starfield of tiny pale-blue square stars moving downward at different speeds. Keep the game visually minimal, crisp, and neon-colored, with no images required: draw all ships, bullets, pickups, particles, and enemies with simple canvas geometry.

The player controls a small cyan spaceship near the bottom of the screen. Draw it as a pointed geometric fighter: a cyan polygon with a nose pointing upward, small side fins, a lower center notch, and a pale cockpit ellipse. The ship moves horizontally only, clamped inside the screen margins, using Arrow Left/Right or A/D. It should also support touch controls: large translucent circular left and right buttons at the bottom corners containing triangle arrows, plus a circular translucent red/pink FIRE button centered along the bottom. Holding Space (or the on-screen FIRE button) continuously fires.

Start with a centered instruction overlay on top of the playfield reading "Arrow keys / WASD to move" and "Space to fire · collect power-ups", with a rounded cyan "Launch" button beneath it. The game begins when Launch is pressed, or Enter/Space is pressed while on the start screen. Hide the overlay during play. The HUD is fixed at the top: left-aligned cyan text in a bold system font showing exactly the changing values in the form "SCORE 0 · WAVE 1 · LIVES 3 · SHIELD 0"; right-aligned yellow text showing "POWER: NONE" or the active power and remaining seconds.

Gameplay is an endless downward enemy assault. Spawn ordinary enemies from random horizontal positions just above the top edge roughly every 0.85 seconds initially, with the interval shortening slightly as the wave rises but never below 0.22 seconds. Enemies descend with speed around 70 plus 5 per wave, with slight random horizontal drift and sinusoidal side-to-side motion. Draw ordinary enemies as inverted purple angular triangular ships with a small pale rectangular cockpit/detail. Occasionally spawn an elite enemy (chance increasing with wave, capped at 28%): it is larger, red/pink, has 3 hit points instead of 1, and a thin gold outline. Ordinary kills award 10 points; elite kills award 30 points. Destroyed enemies produce a brief burst of small colored square sparks. Every 100-ish points, advance the displayed wave using 1 + floor(score / 100).

Bullets travel straight upward very quickly, drawn as short cyan vertical rectangles. The normal firing cooldown is 0.22 seconds. Holding a power-up called RAPID changes the cooldown to 0.11 seconds. A DOUBLE power-up fires two bullets per shot, offset horizontally and colored warm yellow; normal bullets are cyan. Bullets disappear beyond the screen and collide with enemies. A collision subtracts one enemy hit point and creates a small spark burst; when an enemy reaches zero HP, remove it and award its points.

Spawn a falling power-up every roughly 7–14 seconds at a random horizontal position. It falls at about 90 pixels per second, spins, and is drawn as a rotating colored square with a dark center letter showing its first character. Types are RAPID (pink, temporary rapid fire), DOUBLE (yellow, temporary two-shot), SHIELD (cyan, adds one shield charge up to 3), and HEAL (green, restores one life up to 5). Collect a power-up by moving the ship within about 28 pixels of it; show a yellow spark burst on collection. RAPID and DOUBLE last 8 seconds, and the HUD should show the active power plus rounded-up seconds, such as "POWER: RAPID 8s". SHIELD and HEAL are immediate and do not become the active power.

The player starts with 3 lives, zero shield, and no active power. If an enemy reaches the bottom or collides with the ship, call a hit. If shield is available, consume one shield charge, briefly make the ship invulnerable, and create cyan sparks without losing a life. Otherwise subtract one life, create a larger pink burst, and grant about 1.4 seconds of invulnerability with blinking/flickering ship opacity. If lives reach zero, stop gameplay and display a dark translucent full-screen game-over overlay with pink heading "SHIP LOST", a final score line, and a rounded yellow "Restart" button. Restart resets score, wave, lives, shield, active power, enemies, bullets, pickups, particles, and timers to the initial state.

Use a simple particle effect made of small square sparks with velocity, fading lifetime, and the relevant enemy/player/power-up colors. Keep the canvas responsive to window size and device pixel ratio, repositioning the player near the bottom on resize. Apply a bold system sans-serif style, subtle text shadows, rounded touch buttons, safe-area-aware bottom/top spacing, and prevent touch scrolling. The result should be playable with keyboard and mobile pointer/touch controls, with continuous animation via requestAnimationFrame and a frame delta capped for stable motion.