Sinistar is now playable on the Apple IIgs

Developer uraniumgun has released Sinistar.GS, a native port of the 1982 Williams arcade classic built for the Apple IIgs. The v0.5 release includes a non-booting 800k ProDOS image containing all the necessary game data to run on original hardware or modern emulators.

Williams Electronics originally dropped Sinistar into arcades with a custom 49-way optical joystick and a dedicated speech synthesis chip. The game is a multidirectional shooter where you mine crystals from floating asteroids to build "Sinibombs" while enemy worker ships assemble a massive demonic spacecraft. Once built, the boss hunts you down while taunting you with digitized speech.

The Apple IIgs is uniquely suited for this arcade translation. The "GS" in the computer's name stands for Graphics and Sound. The motherboard includes an Ensoniq 5503 DOC synthesizer chip. The original arcade cabinet relied on a specialized HC-55516 CVSD decoder to generate the villain's menacing taunts. The Ensoniq chip handles those digitized voice samples natively. This preserves the terrifying audio atmosphere that defines the game.

Missing the 16-bit console boom

Despite its popularity, Sinistar largely missed the home console boom of its own era. An Atari 2600 version was prototyped but never officially released. Instead of getting dedicated cartridge releases on the Nintendo Entertainment System or Sega Master System, the game eventually found its way to home players through compilation discs.

It appeared on Williams Arcade's Greatest Hits for the Super Nintendo, Sega Genesis, and PlayStation in the mid-1990s. Later generations saw it on Midway Arcade Treasures. PC players even got a bizarre 3D sequel in 1999 called Sinistar: Unleashed.

2MB of physical RAM required

Getting the game running on an actual Apple IIgs requires some hardware overhead. The system needs about 1MB of free RAM. Realistically, that means a machine equipped with at least 2MB of physical memory. If your boot drive is loaded down with desk accessories and initialization files, you have to cold-start the computer and hold the control and shift keys to bypass them.

The port runs at the stock Apple IIgs speed of 2.8Mhz. An accelerator card is highly recommended. For those playing on unaccelerated hardware, a built-in FPS limiter helps stabilize the performance.

Analog timers and SNES controllers

The control scheme is flexible. It also highlights some of the quirks of the host hardware. You can play with a standard keyboard using the I, J, K, and L keys for turning. Analog joystick support is included but turned off by default. Reading an analog joystick is inherently slow due to the fixed rate of the hardware timers in all Apple II systems.

The best control option is native support for the SNES MAX controller card. This allows players to use a standard Super Nintendo gamepad. The thrust and turn controls map to the D-pad, and the Sinibombs map to the B button. You just need to set the correct slot number for the card in the configuration screen. Replicating the fluid movement of the original 49-way optical joystick is always the hardest part of porting Sinistar. Having native SNES pad support goes a long way toward making the ship manageable.