Traditionally, sequels have a hard time matching up to the widespread love of their predecessors. However, in the world of comic book films, a few sequels have managed to continue the story of the original film in such a way that it expands the mythology, develops the characters and opens up exciting new possibilities for the future. Here are the five best superhero sequels thus far.

X2: X-Men United (2003)

Bryan Singer’s X-Men may be one of the first films to kick off the modern era of superhero cinema, but its his 2003 sequel that really helped the franchise take flight. Revolving around an attack on Charles Xavier’s (Patrick Stewart) mansion, the film allows for new revelations with regards to Wolverine’s past and finds the X-Men reluctantly joining forces with Magneto (Ian McKellen) and Mystique (Rebecca Romijn). More than just a continuation of the first film, X2 takes advantage of fans’ knowledge of the characters and storyline to date in order to provide one thrilling twist after another. Even though X-Men: The Last Stand would fail to fully capitalize on the Dark Phoenix saga set up here, X2 remains the finest entry in the mutant franchise thus far.