That's strange. Did you run it using the keeper.command script? Cause the error you pasted happens when you run Frameworks/keeper_mac directly from that directory.
Oh, I had no idea I was supposed to use that file! Since I did the same with the other download and you did mention that I though I had to choose the executable for my platform (since there is mac, linux, etc).
I opened it with the keeper.mac this time. It stood sending messages like it was trying to boot or install the program, and it just stopped. I seemed that nothing was going to happen but I waited for some 20 minutes to be sure. When I decided to close the terminal I discovered the game had opened in a separate window but stayed behind everything, lol. So yeah, it seems to work now!
Thanks!
😀