GOG version has 101 Achievements while Steam version has 98.

If what my friend who is pretty well informed about the game and it's development/progress tells me is true, this is because there were 101 Achievements in v1.0 but then after some necessary patching the game received 3 achievements become impossible to get.

I think "Martyr" is one of them, don't know about the other two.

GOG, please remove those achievements. Some people like to 100% their games and they won't be able to do so until this is remedied.

Shut up, you insignificant achievement hunter!

Those three achievements are reserved for the Elder Ones and are beyond the reach of any mortal being.

I'll chant this 1000 times as my punishment.