The way I see it, McClane runs around for about 20 hours, kills about 37,000 storm troopers, suffers injuries which, if inflicted on mere mortals, would require 450 stitches, and still gets enough free time to figure out how the Death Star works, all with the help of a twinkie-eating police officer back on Earth whom he is communicating with on a souped-up ham radio. After 20 hours, McClane figures out the same chain reaction Achilles' Heel the Jedis knew about. After a few hours work, he sets it off just as the Death Star is preparing to fire. McClane, of course, barely escapes the explosion in a hijacked TIE-fighter.
John McClane vs. The Death Star @ WWWF Grudge Match