Watching Pineapple Express, you might wonder if you’ve seen it before; more likely, you’ve seen one of its many inspirations. If you can digest the fact that you’re not being dished out any original fare, the film delivers plenty of fun.

Written by Seth Rogan and Evan Goldberg–who turned their adolescent agonies into Superbad, a charming smutfest about three hormonally freaked-out teenage boys–Pineapple Express delivers plenty of laughs.

The two screenwriters have become major since then, in particular Rogan, who also starred in the family-values comedy Knocked Up and has recently lent his voice to one-too-many children’s movies. In some respects Pineapple Express plays out like a louder, nastier, more violent and ostensibly adult follow-up to Superbad. The exception is Rogan, who had a supporting part in the first film as a slacker cop, has moved far enough up the studio food chain to now take a starring role.

ÊEssentially, the plot revolves around the blissfully funny James Franco as Saul, the drug supplier who finds himself running for his barely cognizant life with steady customer Dale (Rogan), a 25-year-old dating a high school senior. They’re running because Dale witnessed a drug-related murder and then dropped a precious joint (a joint of the particularly rare and exquisite brand of weed the film is titled after) at the scene of the crime. Unsure whether they’re in a comedy or a drama, Gary Cole and Rosie Perez play the ruthless criminals who want the witness dead.

ÊÊThe entire cast delivers smart performances (as ironic as that sounds), and the whole first half of the movie brims with the humor we’ve come to expect from Rogen. Some of the gags involving the side-winding conversational riffs are incredibly funny. When Dale explains to his dealer that he’s a process server, he replies, “You’re a servant? Like, a butler?” As written, that line could go either way, but Franco–fully invested in this stoner’s stoner–makes it sing.

ÊÊThere are two aspects of this movie that keep it only a so-so, rather than great, stoner movie. First, it goes on for an extra 15 minutes too long. A movie like this needs a running time of less than 100 minutes to be effective.Ê Second, the movie never really makes up its mind about its genre. Around the midpoint, “Pineapple Express” falls apart and keeps falling, and the comedy, spiced with considerable, unevenly effective violence in that first hour, goes out the window, and in comes all the gore and the bone-crunching.

All in all, don’t expect a well thought-out, insightful movie. Just go in seeking a few laughs, and if you are willing to take in all of the movie’s absurdity and suspend your disbelief, you’ll at least be entertained.