The first movie includes scenes parodising a great number of Hollywood movies, and the main character is a brave Turkish carpet salesman who saves the world and the attractive princess. (After being kidnapped and taken to a prison ship by some aliens, one of whom impersonated Prince Charles...)
In AROG (2008), the villains return, and send the hero back in time in order to get rid of him, as their leader still wants to get close to the princess, and all this leads to a lot of advetures in prehistoric Earth.
Whereas GORA is a must-see, the second movie is just funny. Nevertheless, it is still recommended.
GORA (Trailer, Wiki, Imdb.)
AROG (Trailer, Wiki, Imdb.)