An Open Source DOS emulator to run old DOS games
A MUD client for Android, iOS, Linux, Mac OS X and Windows
0 A.D. is a free, open-source, cross-platform real-time strategy game.
INSTEAD - Simple Text Adventure Interpreter.
MAME Android Emulator.
Android, DOS, FirefoxOS, Linux, MacOS and Windows all in one..
Cross platform Game Creation Software
Cross platform administration tool for Source Engine dedicated servers
PC-98 emulator for Android phones
A cross-platform «Boulder Dash»-like game in Oberon/Component Pascal