The trailers for the movie were kind of fun, suggesting Jesse Eisenberg was some kind of secret agent who was a complete stoner ... to the point that he didn't remember he was a secret agent. It looked funny. And for the first thirty minutes, it was very funny, with Eisenberg and Kristen Stewart being an incredibly convincing stoner couple who are deeply in love. But the real problem is that somewhere around the thirty minute mark, the movie turns much darker, losing the humour and becoming grim and very violent.
One of the reviews I saw suggested that this was a mash-up of "Pineapple Express" and "The Bourne Identity." This is accurate as far as it goes, but you really need to throw in a big serving of "Mr. and Mrs. Smith" for the dynamic between the lovers and the grand finale in the department store. That pretty much covers it, because there aren't any new ideas here: had they given more time to the charming Eisenberg/Stewart stoner couple, it could have been a lot of fun. But in the end I'd have to recommend passing on this one, because it ceased being fun after thirty minutes and the extensive CIA inter-departmental manoeuvring that follows isn't even well played.