That's odd. I tried all the games and they all launch for me. (aside from Young-sin Fleshdynamics which I knew didn't work with the launcher). Maybe someone more familiar with Godot can post what that error means? The only error I've gotten in the past is when I've gotten the path/names wrong, so make sure you didn't move any of the files around after you unzipped it.
That said, the launcher is just a fancy wrapper so you can always launch the games individually from their folders.