[viraptor]

Your purchased Doom copy of course ; ) (just search for it, come on, the top results give it to you - just like the search results for "how to run myhouse.wad")

[pinkcan]

I just purchased I and II from GOG, they're EXEs; i'm on a macos machine :'(

[thristian]

GOG's installers are made with InnoSetup, you can use a tool like InnoExtract to get the files out of them (source at https://constexpr.org/innoextract/ or in MacPorts/Homebrew).

[bogantech]

IIRC they can be extracted using innoextract: https://github.com/dscharrer/innoextract

Needs to be used with the offline installer files from GOG

[indrora]

You can uh

find them on the internet.

I wont tell you that the record 2020_03_22_DOOM on archive.org has it. I can't confirm.

[anthk]

Or just use freedoom2.wad from the FreeDOOM project and rename it as doom2.wad