Ah, so the flashing sprites and the "walking in the air snowmens" are normal. In that case is it not needed to play the game from the beginning using another configuration, if it can't be fixed.
I only have a savestate from i left off. So I must continue from that point. That means, I need to go back and get the missing gifts. Will look lame in video. But who cares
Will try what you have said tomorrow and upload a new video.