I remember when this game first came out - I bought it then and it had bugs and I have just recently purchased it from GOG ( Gogs patch 1.9 ) and it still has bugs. While so far I have been able to continue to play it - its not a solid title as far as unresolved technical issues.
The Following issues where encountered on Vista.
Game still has memory leak issues just like it did when it first can out years ago. This it seems is still the major issue of what I consider the cause of most of the bugs that tend to pop up. I have seen the following happen so far.
1) Past cut scenes replay.
2) Parts of prevous areas that you have explored get reset.
3) Getting trapped inside the crypt and unable to leave it - do to the main enterance gate closing and locking itself with no way to unlock it.
4) Random excelerated speed of Arx environment.
In addition I have noticed the following:
1) Possible to get stuck in a spot with no way of getting out
2) I had to set the game to windows 98/me compatibility mode to keep from getting random out of memory errors.
Most of the above problems can be worked around by simply reloading a prevous save or rebooting the game.
Shutting all Unnecessary background problems down did not help with the issues.
I would not recommend this Game for those who are looking for a Issue free game.