Several of the characters are named after well known products, Harley-Davidson (motorcycles), Marlboro (cigarettes), Virginia Slim (cigarettes), Jack Daniels (whiskey) and Ol' Grandad (whiskey). Jimi is named after Jimi Hendrix, whom he resembles. Jose (whiskey) is the silent friend.
In the scene where Marlboro Man (Don Johnson) spits in Alexander's (Daniel Baldwin) face, you see the spit appear, then disappear from Alexander's face.
The Ruger Super Blackhawk .454 can deliver a 250 grain (16 g) bullet with a muzzle velocity of over 1900 feet per second (580 m/s), developing more than 2000 ft·lbf (2.7 KJ) of energy. Marlboro Man's shoulder that Harley shot him in would have been blown clean off (to paraphrase Inspector Callahan), not leave him going, "You shot me!"
There is a patch on the jacket Harley (Rourke) wears, that appears and disappears throughout the movie. It's on the front lower right side. It is there when he's standing outside their friends' bar with Marlboro, it's gone when they are inside.
What are the differences between the old British BBFC 15 Version and the Original Version?
A
Due to the usage of a butterfly knife two scenes had to be cut in Britian in order to obtain a BBFC 15 rating. This censored version was later released on VHS whereas all cuts were waived for the DVD release which is also rated BBFC 15. A detailed comparison between both versions with pictures can be found here.