As this is now no longer a 1.x ./play.it script, but a 2.x one, quite a lot of things change ;)
But it should still be quite easy to use:
1. Download the current 2.x library: libplayit2.sh
2. Download the development script for The Witcher: play-the-witcher-1.sh
3. Put everything into a same directory: library, script and installer (as previously)
4. Make the script executable, then run it:
chmod +x play-the-witcher-1.sh
5. Install the game
6. Enjoy ;)
Actually, before following these steps you should remove you current broken installation with:
sudo apt remove the-witcher the-witcher-data
It might avoid some issues related to the new packages not using the same names.
Just wanted to say I was running into the same issue when running your earlier script, but this one works just fine. Thanks for all the effort you put into these!