If you modify some file, just overwrite the old one. Doom 2 shares progs with Doom (it uses a conditional macro) and that's why doom2 progs folder in prety empty.<br><br>To compile, simplest is to copy vcc.exe into that directory where you will be compiling (i.e. progs/doom2) and run compile.bat.<br><br>Makefile is for compiling using GNU make utility (this one comes from UNIX world), and if you ain't using djgpp or cygwin, you should use .bat file instead.