I am 85% thru the DeLear campaign and 30% thru the Warren campaign. In the DeLear campaign the game freezes after I go the the meteor crater and then try to go to the Laboratory to Analyze the Data. The steer head just sits on top of the Lab icon, but doesn't enter the Lab. The game freezes there. In the Warren campaign, the game freezes at different points randomly in the mission where he must save the bleeding gunslinger. This has happened numerous times in both campaigns. I cannot continue the game at this point. Very frustrating.

Are you on the most recent version? Did you read the "Important Info" sticky?