When clicking full screen, Norton detects three files, SONAR.ProcHijack!g43, SONAR.ProcHijack!g45, and SONAR.ProcHijack!g47. Norton recognizes these as high risk malicious files and will delete them and the game. Based on some research, these files have a history of being trojans. However, based on the fact that the game runs just fine unless you click full screen with Norton installed, it's most likely just a harmless file that Norton deemed as having suspicious behaving code. There are instances in which this has caused other game developers trouble as well. I recommend contacting Norton and reporting it a false positive. Good game btw