Missile Command

A faithful recreation of the 1980 Atari arcade game Missile Command, built against the annotated 6502 disassembly of the rev 3 ROMs.

Overview

Defend six cities from nuclear attack by firing counter-missiles (ABMs) from three silos. The game reproduces the original arcade's core mechanics:

• 60Hz game loop with simulated 240Hz IRQ timing
• Slot-based object tables (8 ABM, 8 ICBM, 1 flier, 20 explosions in 5 groups of 4)
• Fixed-point 8.8 missile movement
• Octagonal explosions (corner-chamfered square), color-cycled at 30Hz
• Smart bombs with evasive movement, MIRV splitting, bomber/satellite fliers
• Attack pacing, mercy rule, and scoring multiplier matching the wave guide
• Procedural POKEY-style audio synthesis
• Attract-mode autoplay demo and mouse-driven high-score initials entry

Installation

Requirements

• Python 3.11 or higher
• pygame 2.5.0+ and numpy 1.24+ (see requirements.txt)

Setup

git clone https://github.com/CAG07/missile-command.git
cd missile-command
pip install -r requirements.txt

Run

python main.py

Controls

Keyboard

• A / S / D or 1 / 2 / 3: fire from left / center / right silo
• 1 (from the attract screen): start a game
• F11: toggle fullscreen
• ESC: quit
• On the high-score initials screen: Left / Right cycles the highlighted character, Return or Space confirms it and advances to the next slot

Mouse

• Relative motion: move the crosshair (trackball emulation)
• Left / Middle / Right click: fire from the left / center / right silo, matching the arcade cabinet's 3 dedicated fire buttons (not a proximity/nearest-silo auto-select)
• On the high-score initials screen: move the mouse to scrub the highlighted letter, left-click to confirm each of the 3 initials

Gameplay

Objective

Defend your cities from incoming ICBMs, smart bombs, bombers, and satellites. The game ends when every city (and any banked bonus cities) are gone.

Missile Silos

• 3 silos: Alpha (left), Delta (center), Omega (right)
• 10 ABMs per silo, restored at the start of each wave
• Delta (center) fires at 7 units/frame; Alpha/Omega (side) fire at 3 units/frame, making the center silo best for last-second intercepts
• Maximum 8 ABMs in flight at once across all silos
• An empty silo plays a distinct "can't fire" sound instead of launching
• The HUD shows a "LOW" banner once any silo drops to 3 or fewer ABMs, and "OUT" once one is empty

Scoring

Target	Points
ICBM / warhead	25
Bomber / Satellite	100
Smart Bomb	125
Unfired ABM (wave end)	5
Surviving city (wave end)	100

All points are multiplied by the current scoring multiplier: 1x (waves 1–2), 2x (3–4), 3x (5–6), 4x (7–8), 5x (9–10), 6x (wave 11+). The wave-end tally screen counts up the bonus tick by tick before the next wave begins.

Bonus Cities

• Awarded every 10,000 points by default (configurable via --tournament to disable them entirely)
• Destroyed cities stay destroyed between waves — only silos are restored each wave — until a banked bonus city repairs a random crater
• The banked bonus-city count is an 8-bit value that wraps at 256, matching the original hardware

Command Line Options

python main.py [OPTIONS]

Options:
  --fullscreen         Launch in fullscreen mode
  --scale N            Display scale multiplier (1-4, default: 2)
  --debug              Enable debug overlays
  --attract            Start in attract mode
  --wave N             Start at specific wave (testing)
  --marathon           Marathon mode (default)
  --tournament         Tournament mode (no bonus cities)
  --help               Show help message

Technical Details

Architecture

Based on the original arcade hardware:

• CPU: 6502 running at ~1.25 MHz
• Display: 256x231 resolution
• Frame Rate: 60Hz
• IRQ Rate: 240Hz (4x per frame)
• Video RAM: 16KB (2bpp/3bpp hybrid)
• Sound: POKEY chip (4 channels)

Game Logic

MIRV Splitting

ICBMs can split when:

• Current or previous missile at altitude 128-159
• No missile above altitude 159
• Available slots exist
• Splits into up to 3 additional missiles

Attack Pacing

New attacks don't launch while highest ICBM is above: 202 - (2 × wave_number), minimum 180

Wave Limitations

• Player never loses more than 3 cities per wave
• If 3+ cities destroyed and no ABMs, wave ends immediately
• Attack targeting adjusted to prevent excessive city loss

Smart Bombs

• Maximum 2 on screen at once
• Evade explosions by detecting flashing colors (#4/#5)
• Move toward target while avoiding explosions
• Count as 2 missiles in spawn calculations

Explosions

• Shape: Octagonal (3/8 slope, not 1/2)
• Max Radius: 13 pixels
• Slots: 20 explosions in 5 groups of 4
• Update: 1 group per frame (reduces load)
• Collision: Checked every 5 frames, only affects ICBMs
• No collision below line 33

Performance

• Defers score redraw during heavy frames
• Group-based explosion updates
• Fixed-point math for efficiency
• Optimized rendering pipeline

References

This implementation is based on the official Missile Command Disassembly (revision 3 ROMs):

• 6502 Disassembly Project
• Attack Wave Guide

Original Game

• Title: Missile Command
• Developer: Atari, Inc.
• Year: 1980
• Designer: Dave Theurer

Key Disassembly References

• Attack wave logic: $5791
• MIRV conditions: $5379/$56d1
• Wave end check: $59fa
• Score deferral: $50ff
• Bonus city table: $6082
• Initial city table: $5b08

License

This is a recreation for educational purposes. The original Missile Command is copyright 1980 Atari, Inc.

Acknowledgments

• Dave Theurer — Original game designer
• Andy McFadden — Disassembly documentation
• Atari — Original game
• Based on initial work by BekBrace

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Defend your cities. Save humanity. Good luck, Commander.