I had the same thing. Finally I went in and looked in the package and ran it from the link in there instead of from Steam. It worked.
I went back to Steam load and it crashed. ODD - the only difference was the steam info overlays where in the lower right corner. so I tried to load it again but this time I hit shift tab a couple times to eliminate the steam overlays in the lower right.
it LOADEDIt loaded fine. I tested it a few times with same result. Seems really odd to me, but so far my tests have all been the same.
I finally played it last night and it's awesome. the learning curve is a bit steep because there are so many more options and moves than a typical FPS. I like how in a mission like (I'm in the mansion) you can use any path, window, jump in or out and really use any plan of attack you want. When you die - trying another plan. It really requires patience which I love. I hate just blasting everything that moves. I like stealth and (haven't had this yet in the game, but I love sniping). Reply here if the steam overlay removal fixed the problem for you? Ron in MI.