I've just installed GOG Galaxy and downloaded Gothic. The play button is greyed out in GOGG and when I go into the directory and try to launch from the exe directly that doesn't work either, wtf?

Download the offline installers - have fun.

Where and how?

In your account (under games)

It tells me to insert a disc when I try that...

Screenshot please

Took the words right out of my mouth...

Seriously this is REALLY starting to PISS me off now. I just wanna play the games I payed for why does this have to be so fucking hard?

I managed to install the backup installer and when I clicked on play it just took me right back to the greyed out play button on GOGG... ><

https://support.gog.com/hc/de/articles/213515389-Gothic

https://www.gog.com/forum/gothic_series#1567619150

Seriously there is a dedicated forum section for Gothic games series with lots of available solutions.
https://www.gog.com/forum/gothic_series

In your case just unistall the game and Galaxy client (if simple quit the application is not working for some reason) for a time being and install the game using offline installer, give us the screenshot where it asks a game disk to be inserted because we are curious

I got the please insert disc message when i tried to launch the installer before downloading part 2. After downloading part 2, i managed to run the installer, but instead of launching the game it just took to GOGG launcher, wtf?

Run the game from its exe in the Gothic\system folder, don't use the Launch shortcut - that's for Galaxy.

The "please insert disc" message is what I got with the setup language set to German. When I tried again after uninstalling Galaxy with the setup language set to English it said "cannot locate file" instead.

Now it keeps telling me it cannot locate the file even rhough I've already downloaded it.

As I stated in my OT, that didn't work for me either.

Dude, uninstall the game before reinstall.