Thanks GOG! And thanks these excellent devs too.
This game is very smartly done.

Just a heads up everybody:

Having a *tiny* bit of trouble with the new mod, apparently:
http://www.gog.com/forum/defenders_quest/new_mod_not_working

The issue is something in the GOG build won't let the game produce folders correctly. I'm investigating and will send an update to GOG ASAP.

The good news is, the rest of the game should work just fine, you'll just have to wait a bit for shiny mod support.

UPDATE:
Found the bug! It's fixed locally for me, I'm getting a new build to GOG ASAP. This will be version 1.1.00

Thanks for the update and for moving so quickly to squash this bug!

Even while we're waiting for the new build with fixed auto-installer to go up, the new mod should work if you install it manually.

To install manually:
1) Go to your documents directory (mine is "C:\Users\larsiusprime\Documents")
2) Create a "DefendersQuest" folder
3) Create a "mods" folder inside of that
4) Create a folder for your mod (say, "spacedefenders")
5) Unzip the contents into that folder, such that "settings.xml" and all the other files are right inside of "spacedefenders."

Review:
GOOD:
C:\Users\YourUserName\Documents\DefendersQuest\mods\spacedefenders\settings.xml

BAD:
C:\Users\YourUserName\Documents\DefendersQuest\mods\spacedefenders\anotherFolder\settings.xml

Hope this helps tide everybody over! Not sure what the mac directory equivalents are, but the starting point is the "Documents" directory.

thank