The base ingredient - Gerard Butler will please the taste of some but not others as a convincing 'give it all you got' action hero. Take a good amount of Die Hard and add a dash of Red Dawn. Mix in a pinch of James Bond. Remove any Jack Bauer as he would have prevented any of this from ever happening to start with. Add more graphic violence and seriousness. Top off with a quality actor that everyone loves - Morgan Freeman and leave for 120 minutes. There you have Olympus has Fallen.