There was buddy movies before Lethal, like the underrated gem Thunderbolt & Lightfoot, but this kickstarted a typhoon of copycats. Made with a very modest budget, Lethal 1 was a very grim and real movie compared to the 3 sequels. Groundbreakingly focusing on suicidal tendensies, seen trough Riggs, a manic, depressed cop, who is a menace to himself and everyone else. The big reason Lethal 1 became a classic isnt the story, but the chemistry between Danny Glover and Mel Gibson. The latter creating intense situations, tormenting the former. Too often Gibson gets the credit for Lethal Weapon's success, but it's a team effort. Glover grounds it in reallity, giving us a normal family man to keep Gibsons gung-ho somewhat in check. Not to mention Richard Donner, who used all his tricks to get the best out of a tiny budget. They don't make em like that anymore. Litterarly... they would be sued for some of the crazy stunts.
Review of Lethal Weapon
