If you don't have plans to see this movie, you can check the spoilers here and then come back.
This movie started out with Matt Damon doing a deadpan monologue (he was technically talking to his son, but it may has well have been a monologue) about the various uses of corn, and I immediately loved it because everything from his cadence to pronunciation is hilarious. In fact, Damon continues with these random fact voiceovers throughout the film and I could have listened to just that for the full hour and forty-five minutes because I laughed out loud nearly every time. However, outside of those little nuggets of goodness, the plot is so byzantine and confusing that I couldn't follow it to any great degree of satisfaction and found myself extremely frustrated. Damon's Mark Whitacre is a bio-chemist turned executive at an agricultural company who gets involved in an FBI investigation initially geared at tracking a mole but that goes through several evolutions even as different layers to his psyche are uncovered. It's extremely hard to keep track of and thus get invested in; every time you think you may have things figured out, there's another twist that feels tacked on and unnecessary. On paper, the cast looks fantastic, but for the most part they're just bland wallpaper, typified by Joel McHale's dull performance as the "bad cop" (I think) FBI agent. Only Scott Bakula and Tony Hale even briely break out of the supporting player rut as a granite-faced but idealistic agent and put-upon lawyer respectively. Yet despite all this, Damon is absolutely incredible, doing beyond a 180 (a 270?) from his typical action characters and proving quirky and funny as a schlubby middle American then taking an inspired turn as a manic nutjob in the latter act with the tradition proving entirely seamless. Damon's performance is so good that it kept me laughing and curious through what would have been a kinda crappy movie buoyed on his shoulders (and with a delightfully weird soundtrack) into at least average.