This only started recently. So, I suspect that either the game files or my hard-drive have been corrupted. First problem was I built a city on a forest tile then tried to cast a spell on it and got the error message "cannot cast on forest". That may actually not be a glitch, but I suspect it is in that it's never happened before in over 1,000 hrs of play. 2nd issue- completed the "Terrorized workshop", got the screen to choose either the warding shield or metal, chose the shield but never received it and quest still shows as incomplete. Started a new game without changing any settings, but instead of 10 opponents was assigned an ally. Restarted the game again, but got no reward when exploring a lost battlefield. I had very similar issues to this a couple years ago with this game. At that time there was a button in Steam settings labeled "confirm integrity of game files" or some such, clicking that resolved the issues immediately. Unfortunately, that button no longer appears to exist, so I'm left with the standard procedure of posting to game support and screaming for help.
Running Windows 7 Pro, btw- if that info helps at all.