Lynch indeed was a scarey guy on screen. I recall him in Galactica, 1980, Buck Rogers, The Phoenix (I barely remember him in the Blue Thunder TV show, did he also do an Airwolf episode?) and a few other things. Sure he happened to do things a bit over the top, but that is what made him memorable (and it kept him getting a steady paycheck for his work).
I have to admit, Invasion USA was kind of forgettable as a film, EXCEPT for Lynch's role in it as the main bad guy terrorist (with his repeating shot rocket launcher that could fire 11 times without reloading). I will miss him.