So let me add my experiences with last update.
First of all, it showed me that download was about 509 MB big. I thought that this will be no big deal, but wrong...
As others already mentioned, it started to download much more, in my case, the "!Temp" dir was about 50 GB big. This is the first thing that should NEVER happen. So already the first thing is simply wrong design.
Then, the update stucks at several points. For me, at 54%, at 84%, at 91%. There is no further information, what happens here. No progress bar, nothing. This leaves the user thinking if something went wrong, was crashing or other. Second thing that should NEVER happen.
Next, the update takes too long. In my case, I stopped it yesterday evening, simply because it really made me angry. I restared the updatre this morning. If I put all time together, the update took over 6 hours. Third thing that should NEVER happen for 509MB of update.
In the meantime this morning, just for fun, I took another PC and started to download the whole game to another hdd. It took less than 1 hour - and after having started it, I had version 1.06.
So... Could anyone please give the responsable dev a hi(n)t so that he/she will notice that this update mechanism is simply big shit? For the gog guys, you could take off the update functionality and simply tell the people to reinstall the whole game from scratch, because this is much quicker...