Originally Posted by Santa Sangre
I always had the impression he was playing himself, just like Nicholson in "As Good...". The german dialogue passages added tremendously to that conclusion, also the longer screen presence. He is imo better when being funny, serves his Austrian/Vienna character pretty well. Sometimes I even felt he was the leading actor.
Though, the performance of the sarcastic character in Basterds was executed flawlessly.
I think you're understating his Basterds performance a little bit. He was sarcastic, but he was also terrifying, charming, funny, manipulative, and highly intelligent, all while having to speak four or five different languages fluently. The diversity required for the Landa role, is insane.
Don't get me wrong, he was great in Django, but he was basically playing one dimension of the Landa character throughout.