I can't get this to work whatsoever, mounted the drive and what not, but won't run the "SETUP_UNDER_A_KILLING_MOON(2).EXE.PART"

Have no idea what to do as this is my first time using DOSBox as well

Wait, can you explain what you're doing? Are you trying to install the game with DOSBox?

Sounds like you are making it more complicated than it needs to be. The games from GOG come with their own installer and have DOSBox pre packaged with it. You just need to run the executable you downloaded and it will take care of everything for you. However, the fact that you have a file ending with ".PART" would seem to indicate that it did not download correctly as the installer should just be called something like "SETUP_UNDER_A_KILLING_MOON.EXE"

I just re-downloaded everything and it comes up with a Download Error that says "setup_under_a_killing_moon.exe.part could not be saved, because the source file could not be read."I guess I actually have to physically sit here and wait for it to download without idling my comp so it finishes all the way through, we'll see how it goes.

Oh, I see. Delete the ".part" from the name. A message will come saying if you're sure you want to rename/change the extension. Hit yes.

I think the installer thought it was part of a series of files, when it's only one.

So, basically what cogadh said.

Say, you happen to use FireFox? If yes...

.PART files are files that haven't been completely downloaded- you CANT open them.

If the file's still a .PART even after the download has completed, delete the .PART file and try again. It happens sometimes. It is quite unfortunate, because as long as it's a .PART file, it's not correctly downloaded.

Even if you rename it, you'll have a large chance of having ended up with a broken file.

Just redownload it, and it'll work fine.

I'm playing this on a Macbook.
I opened the exe. file with Crossover Games and imported the DOS files into Boxer (which is an excellent program for running DOS games on a Mac!).