A downloadable Leaf
A non-standalone, C library for MS-DOS games. Includes mouse support and advanced video support. Guess what. It even supports bitmaps (trough you need GIMP because MS-Paint messes up everything, but dont worry, support for MS-Paint will be added soon!)
The game engine, as said earlier is not stand alone, you would need to compile it along with your game. One of the recommended compilers for this game engine is TurboC (specificaly version 2.1).
Windows Vista, 7, 8, 8.1, 10 (32/64-bits)
To run you would need special software for DOS emulation. Set it up according to your emulator.
Windows 3.1, NT 4.0, NT 5.0, 95, 98, ME (16/32-bits)
No special software is requiered, just the compile rand thats it!
Windows XP (32/64 bits)
Depending on your architecture. If it is 64-bits use the first installation way (the one above). Else just run it as normal.