While the marketing campaign doesn’t make a huge deal out of it, this weekend’s Kingsman: The Secret Service is, in fact, a comic book adaptation. It’s based on a six-issue limited series called The Secret Service, a 2012 comic written by Kick-Ass writer Mark Millar (whose work gets optioned by studios so often that it’s easy to call his comics movie pitches), with art by legendary Watchmen artist Dave Gibbons.
Even though the broad strokes are all there, Kingsman is a very loose adaptation, with dozens of changes to the source material. It’s enough to consider the comic and movie entirely different stories—knowing one won’t necessarily ruin the other, although the changes made to the film are almost all for the better. Here are five of the biggest ones. Spoilers ahoy!