Asteroids++ — Player's Guide

Classic Asteroids reimagined with procedural polygon asteroids, wrap-around physics, pixel-perfect collision, infinite rounds, and an accuracy streak bonus. The ship rotates and thrusts in zero-gravity; each asteroid you shatter splits into smaller, faster fragments until nothing remains.

Quick Start

Key Action
Arrow Up Thrust
Arrow Left / Right Rotate ship
Space Fire bullet
Enter (game over) Restart
P Pause / resume
Escape Open settings

Your score appears below the canvas; the current accuracy streak sits alongside it. When you die, press Enter to start a new game.

Gameplay

Rounds and Multiplier

Each round spawns a fresh wave of asteroids. The round multiplier increases every wave, amplifying your score:

Round Asteroids Multiplier
1 5 ×1.0
2 7 ×1.5
3 9 ×2.0
4 11 ×2.5
5 13 ×3.0
N 3 + 2N 1 + (N-1) × 0.5

When all asteroids are cleared the next round begins immediately. Your ship respawns centre-screen with a brief invincibility period (indicated by flashing).

Asteroid Tiers

Size Radius Base Score Splits into
Large 90 px 20 2 Medium
Medium 50 px 50 2 Small
Small 25 px 100 Nothing (destroyed)

Each asteroid is a unique irregular polygon — no two look alike. Splits inherit the parent's velocity plus a small random offset, so fragments scatter unpredictably.

Accuracy Streak

Every consecutive asteroid hit builds your accuracy streak. The higher the streak, the more bonus points per hit:

  • +10% bonus per streak level: streak 1 = +10%, streak 5 = +50%, streak 10 = +100%
  • Streak resets to 0 when a bullet expires without hitting anything, or when your ship is destroyed
  • Max streak is capped at 20
  • Current streak is always visible next to your score: Score: 1540 | Streak: x7

Strategy: fire deliberately. Spraying bullets into empty space resets your streak. Wait for a clear shot and aim carefully to keep the bonus climbing.

Lives and Death

You have a single life per game — no extra lives or continues. When the ship is destroyed the game is over, your high score is checked, and you can restart with Enter. The accuracy streak resets immediately on death.

Scoring Summary

Source Points
Large asteroid 20 × round multiplier × streak bonus
Medium asteroid 50 × round multiplier × streak bonus
Small asteroid 100 × round multiplier × streak bonus
Streak bonus +10% per streak level, multiplicative with round multiplier

Example: destroying a large asteroid in round 3 (×2.0) with a streak of 5 (+50%):
base = 20 × 2.0 = 40
bonus = round(40 × 5 × 0.1) = 20
total = 60

Controls

Default Key Bindings

Action Default Key
Thrust Arrow Up
Rotate left Arrow Left
Rotate right Arrow Right
Fire Space
Pause P (not rebindable)
Settings Escape (not rebindable)
Restart Enter

Re-binding Keys

  1. Press Escape or click the cog icon to open Settings.
  2. Click the bind button next to the action you want to change (e.g. "Thrust").
  3. Press the desired key on your keyboard.
  4. The button updates to show the new key.

If you bind a key that is already in use, the old binding is reassigned back to its default. P and Escape are reserved and cannot be changed.

Settings Panel

Press Escape or the cog icon to open settings. All changes save automatically to your browser's localStorage and persist between sessions.

Key Mappings

As described above — rebind any action by clicking the bind button and pressing a key.

Colour Themes

The game supports two theme modes:

Default (Bootswatch) — inherits colours from the active Bootswatch CSS theme (light or dark). When the page theme changes, the game updates automatically. Not editable.

Custom themes — click + to create a named theme. Colour pickers become active for each element:

Element CSS variable (default) What it colours
Ship --bs-primary The player's ship polygon
Bullets --bs-danger Bullet squares
Asteroids --bs-body-color All asteroid polygons
Stars — The starfield dots
Background --bs-body-bg The canvas fill colour

Changes save in real time as you pick. Themes can be renamed (click the name) or deleted (click ✕). Switch between themes at any time, even mid-game.

Seven visual and audio toggles live in the left sidebar. Each can be changed mid-game without restarting:

Toggle Effect when OFF
Sound Mutes all audio (fire, explosions, thrust hum)
Shake Suppresses camera shake on hits and death
Stars Hides the starfield background
Glow Removes the neon glow (shadowBlur) from all polygons and floating text
Hit FX Suppresses floating +N score popups and the hit sound
Thrust FX Hides the warm-coloured thruster flame particles behind the ship
Particles Stops explosion debris from spawning when asteroids or the ship are destroyed

All toggles default to on and are persisted in localStorage.

Focus Mode

Click the eye icon next to the score to toggle focus mode. The sidebars dim (remaining visible but low-opacity), letting you concentrate on the canvas. Click again to restore full UI.

High Scores

How to Submit

When your ship is destroyed, the game checks if your score qualifies as a top-10 high score. If it does, a modal appears with a countdown timer:

  1. Enter your name (max 20 characters, or leave blank for "Unknown").
  2. Submit before the timer expires.
  3. The high score list in the right sidebar updates immediately.

Anti-tampering

Score submissions use a signed token that expires after 10 seconds. You must actually play the game to get a valid token — direct API calls are rejected. Each token is single-use and tied to the exact score it was issued for.

Visual Effects

  • Thruster flame — four warm-coloured particles per frame emit from the ship's rear while thrusting, with a wider spread and shorter life than explosion particles
  • Explosion particles — bursts of 12 particles (asteroid) or 25 (ship) scatter with randomised velocity, inheriting 50% of the destroyed object's momentum
  • Screen shake — hits trigger a 3px shake, death triggers 10px; decays over time
  • Score popups — floating +N text rises from each destroyed asteroid and fades over 1 second
  • Starfield — 200 stars across three depth layers, with sine-based twinkle and slow downward parallax drift
  • HiDPI canvas — automatically renders at your display's pixel ratio for crisp text and polygons on Retina screens

Tips and Strategy

  1. Build your streak early — the first wave has only large asteroids, which are slow and easy to hit. A streak of 5–10 from round 1 carries bonus momentum into harder waves.
  2. Don't spray — every bullet that misses costs you your streak. Fire when you have a clear line.
  3. Use the wrap — asteroids and bullets wrap around all four edges. A shot fired toward the right edge can hit an asteroid on the left edge of the screen.
  4. Large asteroids first — they're worth fewer base points but split into two medium asteroids, each worth 50 (before multiplier and streak). Clearing large asteroids quickly fills the screen with smaller, more valuable targets.
  5. Stay central — the centre of the screen gives you the most time to react to asteroids approaching from any direction.
  6. Kite — thrust in the opposite direction from the densest cluster of asteroids to buy space, then turn and fire.

File Reference

File Purpose
/asteroids Play the game
/docs/arcade/asteroids Architecture documentation
/docs/arcade/build_asteroids Step-by-step rebuild tutorial
static/js/asteroids.js Game engine (~1360 lines)
templates/asteroids.html Page layout and UI
src/routers/asteroids.py Server route
src/routers/highscores.py High score API
src/store.py Score storage
tests/js/asteroids.test.js 53 unit tests