Defender for the Atari ST/STE/Falcon

This is a port of the Williams Defender arcade game to the Atari ST/STE/Falcon, based on the published 6809 assembler source code and assets on GitHub: www.github.com/Historicalsource/defender

AtariCrypt Review: https://ataricrypt.blogspot.com/2025/06/defender.html

Requirements

Defender supports 50Hz PAL Atari ST/STE, Mega ST/STE, and Falcon030 computers with at least 1MB RAM.

Vertical overscan is used to match the original's 240 pixel heigh gameplay area. An overscan test is available in the game menu (accessed by pressing F3) that can be used to adjust your display until the full frame is visible.

High quality sound samples are used on machines with DMA sound (STE/Falcon) and at least 2MB RAM.

The game can be played with the Keyboard, or a Joystick attached to port 1, or a Joypad attached to Enhanced Joystick Port 0 (where available).

Origins and Attribution

The original arcade Defender was designed and programmed by Eugene Jarvis, Sam Dicker, Larry Demar, Paul Dussault, et al.

It was produced and manufactured by, and is Copyright (c) 1980 Williams Electronics, Inc.

For this port I did the platform, sound, and graphics programming to the Atari ST, and translated the original 6809 gameplay logic.

My work was technical. The gameplay belongs to the original authors. If it feels like Defender, then that's because of them. If it doesn't, then that's because of me.

This is a free port written for Atari ST enthusiasts. If you're a casual gamer looking to play Defender then the original can be played via emulators such as MAME, or even in your browser at the Internet Archive: https://archive.org/details/arcade_defender

Open Source

This program is free software and the source code is available on GitHub: www.github.com/therealsark02/defender

This project was a lot of fun. I hope you enjoy it.