I was absolutely delighted when I found out that most East German home computers (and probably most Eastern Bloc computers in general) are supported in the MESS emulator. About a year ago I spent a few weeks to get some of my old KC85 games from the 80's running in the browser via JSMESS and emscripten (no sound support yet at that time unfortunately):

http://www.flohofwoe.net/history.html

MESS has since been merged back into MAME, and has been moved to github:

https://github.com/mamedev/mame

And some info on how to get started with coding on the KC85:

http://flohofwoe.blogspot.de/2014/11/new-adventures-in-8-bit...