I just installed the game with the 64bit installer but it refuses to play fair.
The first level works just fine but in the second level the issues start to pop up including I think the inventory/esc bug problem people here describe.
Sometimes it is not possible to access these.
The game also gets "stuck" from time to time when using the inventory/options menu and the afterwards it becomes impossible to close the game.
I had to reset my computer once when that happened.
I guess I should install the game if I ever want to play it again on "native" hardware and OS.
On a sidenote, I have forgotten how tank like the controls are.
After having played Emperor's Tomb it is such a drastic step back.