spindown: Normality is the original UK version with British voice actors as opposed to the re-dubbed US version. Of course, that's not missing content or anything like that, but it's something people might want to know before buying.
Psyringe: Let me get this straight: There are dubbed English versions of originally English voice acting? (Yes, I get the difference between BE and AE, but that still seems _very_ odd to me ...). Will they start re-dubbing games because one voice actor didn't use the local convention of pronouncing "tomato" next? ;)
Yes, that is correct. There are two different English-language versions of the game. I was very surprised to learn about this, too. However, I believe it's not about accents, but about the quality of the voice acting. Apparently the American publisher of Normality thought that the British voice acting was poorly done and not good enough for the American market, so they re-recorded everything. Some people like the American version better while others prefer the British original. In any case, it's something that might be worth mentioning since for some people the GOG version will be different from what they remember.