frankd3: I would just like to add that the second uninstall entry (the one without the Fallout icon) does not get removed during the uninstall. I had to remove it manually.
I tried reinstalling again and this time both Tactics Add/Remove Programs entries had the Fallout Icon. That was a surprise.
But the registry key that is left behind after uninstall is this one:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Fallout Tactics
The good one appears to be:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Fallout Tactics_is1
That's the one that is used during the uninstall and gets deleted.
Yes, I noticed the IS1 version myself the other day and was thinking it might be related to this but then discounted it because I saw a few non-gog entries that had it as well. I figured it was that user account control thing going a bit weird as it sometimes does.