I'm currently playing the game just fine with Win10 using the following step-by-step guide: https://forum.worldofplayers.de/forum/threads/1561915-Gothic-1-startet-nicht-GOG-Win10?s=d1aa7683a734aa4f7903d45d57bdb12e&p=26506633&viewfull=1#post26506633

Though I've no idea how good the unofficial English patch is, as the guide recommends the German version and I play it on German.

Google translate should offer a sufficient enough translation to figure it out.

Description of that game "It will run under Win7 Win8 Win10" it does not run under Win10 !!!!

Now im able to start the game, it was very difficult : https://forum.worldofplayers.de/forum/threads/1561915-Gothic-1-startet-nicht-GOG-Win10

The website is in german!