There are two versions of the film (not including the Blu-ray version); one has the theatrical release, and the other has an unrated version in addition the theatrical version. I received the theatrical version so I can’t comment on the other, however Year One was originally rated R and was trimmed to PG-13. So the unrated version may just be the original version of the film; however these days unrated just means some gratuitous female nudity and while I love the female form, naked women wouldn’t improve this film.
There are a good number of extras. First up is a commentary with Jack Black, Michael Cera, and director Harold Ramis. The trio really enjoyed working on this film and has a good time telling behind the scenes stories of shooting the film, which scenes were digitally enhanced, how certain stunts were performed, and the historical accuracy. Cera is quiet more often than the others since this commentary was his first time seeing the completed film. They also talk about thoughts for a sequel which means this commentary was recorded before its weak performance at the box office.
"Deleted Scenes" has a handful of scenes cut for time and as they didn’t add much to the plot weren’t missed.
"Extended & Alternate Scenes" lengthen certain scenes (which wasn't necessary) and allows viewers to see other versions of scenes that weren’t as strong as what made it into the film.
"Line-o-Rama" — Anyone who is familiar with Judd Apatow’s films know this is a staple of his films where the actors improv some of their lines. Since Apatow is a producer on Year One, it’s not surprising to see that feature here and it's funny.
"Gag Reel" is your standard collection of flubs and stifled crack-ups. The cast and crew enjoyed making this film, and it’s too bad the final product doesn’t stack up to the star power within.
"Year One: The Journey Begins" is the making-of featurette, which has entertaining interviews with this cast and crew where they share their thoughts on the making of the movie.