Groen is developed with Visual C++ 6.0 using MFC. It might have problems compiling "out of the box" with newer versions of Visual Studio, something i haven't tested.

The target configuration is set to Debug by default.
When the editor is compiled and run with that configuration, on startup it will look for "hack.nes" in the editor's folder instead of showing the Open File common dialog.
Since the ROM can't be opened the editor will quit with an error.
To change this, set the configuration to "Release" instead. Or, in BioEd.cpp, modify the InitApplication() function which is where it loads the initial ROM file.

The following modules (along with their headers) doesn't rely (directly) on the Windows API:
	Core.cpp
	BitMapOp.cpp
	Com.cpp
	TileRen.cpp