Doubletalk is a game of audio manipulation which I wrote in Z80 assembler for the Gameboy. It synthesizes three loves of mine: audio, cheap hackable hardware, and Z80 assembler.
Cheap hackable hardware such as the Gameboy has enormous potential: it would cost considerably more to interface a microcontroller to buttons and a color screen than to buy any Gameboy selling on eBay.
Now more than 20 years old, the Z80 has long since been abandoned for use in microcomputers. However, it has found its way more recently in less expensive digital organizers and game machines.
Doubletalk, a two player audio-manipulation game was my first serious endeaver with the Gameboy. The game used the Pocketvoice, a Gameboy cartridge with a built-in amplified speaker and microphone. In Doubletalk, players record themselves, reverse their recordings, then try to guess what each other is saying.
My work on Doubletalk and my other hacking projects with the Gameboy such as Gameboy Hardware Interfacing eventually led me to use the Gameboy as the platform for an assembly language programming course I taught at Wichita State University in 2008.