I have not played Myst in probably 30 years, but I remember the one brother (I think the red one) tries to trick you into completing his book instead of the other one or something and I think they had different endings. It was definitely unique and innovative for the time, I miss when PC had high IQ games like Myst/Riven. I was big into King's Quest and Space Quest back in the day, that whole genre of games is largely dead.