Can't seem to build

[GB-CG]

I tried to convert the doomu wad but when I clicked on msys2.bat, it closed itself instantly despite having C:\devkitPro\msys2\msys2_shell.bat in place, I think?

Path is C:\devkitPro\projects\GBADoom\GBADoom-master\msys2.bat

Although KippyKip's instructions on his fork worked for me, I was able to build the SVN version of doomu.

Also, typo at \source\doom_iwad.h in your instructions.

[RetroGamer02]

I think I can help.
I use this in my msys2.bat to build
set HOME=. C:\devkitPro\msys2\msys2_shell.bat make
Which is a little bit different than what is in the repo.

[GB-CG]

That didn't work, I'm afraid.