Humor wise, it was good. It was nice to see something other than goofball “American Pie” comedy, or slapstick “Scary Movie” comedy in a movie. The dead-pan between Duchovny and Jones was very refreshing and very funny. And the initial premise had lots of potential - how the heck are they going to deal with this alien invasion?
Beyond that, however, the movie fell apart, and it failed in all the ways that make ghostbusters good (its hard to not compare the two, as they follow very similar structures). For one thing, the movie doesn't take itself seriously. For the first half of the film, you have everyone treating the situation in the same light that New Yorkers treat the Gozer situation - which genuine fear, despite the comedic aspects of the film. Then, half way through Evolution, the movie started taking itself as a joke. I recall the scene where they used the periodics table to go “down three and over two” or some such crap to find out how to destroy the aliens. The movie descended into stupidity and self-parody from there, ruining it.
In addition, some other points. The movie essentially goes between two or three major locations, providing a very boring movie. There are a lot of scenes that don't belong - one between Duchovny and his ex-wife, which had no connection to the rest of the film (perhaps there had been more in the film once, such as the Janine/Egon romance that once existed in Ghostbusters). Similarly, there is a scene in which they're driving down the high way inexplicably singing Play That Funky Music. No reason given (tho i believe, from previews, that there was supposed to be a scene where they're attacked by aliens from the sky, but i think it got cut out). You can argue that these scenes are funny and that's the sole reason they should be in the film, but come on. Reitman has style, and VERY good comedic timing. By the former logic, he would have left the Fort Detmerring scene and the honeymoon scene in Ghostbusters, because they were also funny. Evolution felt like he failed in a lot of its timing.
And if you want to go by either critics (38 good reviews vs. 54 bad) or the box office returns, which were terrible, both agree with where i stand.
dont get me wrong, i was hoping it would be good. it is the first film that Reitman has put “From the Maker of Ghostbusters” as an endorsement - and i know that if it was successful, he might have pushed for ghostbusters 3. Again, i personally loved the comedic aspect (tho the two hillbilly guys and Sean William Scott could have been killed by aliens, for all i cared). But overall, it was a pretty bad movie, and I dont think we'll be seeing a GB3, or any other large budget movie from Reitman anytime soon because of it.