This is a movie for all the shippers out there, pure and simple. If you're in it for the aliens, the gore, the action or have never seen X-Files before, you'll be sorely disappointed. BUT, if you felt robbed during Fight the Future and throughout the series as we witnessed Mulder and Scully's sexual tension, then brace yourself - you'll LOVE I Want to Believe. This movie is a huge love letter from Mulder and Scully to the shipper fans! And if you are such a fan, stay till the end of the credits for something extra special.
The acting by DD and GA is outstanding - they are phenomenal actors and brought their characters right back to life, without any of the awkwardness of not having stepped into these roles for the past 6 or so years. The onscreen relationship and dynamics, as mentioned, is fantastic. My critique is that the story had no wow factor in terms of why CC made this into a big screen movie versus a TV movie. Perhaps because the budget was low? Thanks FOX. And FOX also blew it by not promoting the movie.