I really can't play the game like this, so I'd be very happy if there's a solution. I bought the game on Steam earlier today, and since then I've been trying to play a simple game against AI to understand the controls and such (the Tutorial is good to have, but no substitute for experience). What I do is, I go to the multiplayer, host a game, add one AI, and then just start without changing anything else. The game runs without incident until combat would start, then it completely freezes: nothing in the window moves except the cursor, and shortcuts such as alt+TAB and alt+F4 don't work, though the music continues. ctrl+alt+delete allows me to open the task manager, though the game window still has my mouse captured so I can only navigate it using my keyboard.
I have tried multiple times and the result is always the same. Even running as Administrator or using Compatibility mode have little effect; compatibility mode makes it so that opening the task manager doesn't minimize the game window, so not only do I have to use my keyboard I also have to do it blind, but I managed.
I ran DxDiag to get a complete and up-to-date system specs, but the summary is here:
i7 3rd gen QM CPU
NVidia 660M GPU w/ latest beta drivers
Windows 8 64-bit
Steam Beta client
Game on Ultra preset, 1080p resolution (chosen by the game's automatic setting button)