Tony, that's weird: the link is opening just fine for me. Here is the game on Steam:
https://store.steampowered.com/app/1512050/World_Turtles/
Baldiron, I'm not sure that the people creating
this particular game are Discworld fans. The only thing this has in common with Discworld is that the world is on a turtle's back.

There is no mention of the elephants, or Great A'Tuin, or anything else to do with Discworld. There's not even a mention of the turtle's shell.
So, given that the whole "world on a turtle's back" is based on Hindu mythology (I think? please correct me if I'm wrong) and not original to STP, I think they can do what they like.
(P.S. before someone flames me for saying that the "world on a turtle's back" idea isn't original to STP ... please remember that STP took the original idea, but named the turtle, added the four named elephants, and created an original world based on that. The
only thing that wasn't original about the Discworld is the "world on a turtle". Everything else is completely original.
I know I'm probably preaching to the choir, here! Just covering my you-know-what)