Eddie went to a movie theater with his friends to see the new fantasy flick (The Gremlins Attack the Mouse People) and they sat through the movie twice.
that's one way you could do it. when using parenthetical elements, you want to be aware of what exactly parentheses do--they offer further information, almost like an aside of sorts. it isn't necessarily vital information and most people use parentheses instead of commas to show an exception or give extra information. the best way, i would say, to add parentheses to these sentences is by inserting the "extra" info that follows "flick." the name of the movie isn't necessarily important, but you include it anyways.
