About half way through the film, Kelly is trying to explain to Gummer how to fire his six shooter. Before handing Gummer the pistol Kelly exclaims, "This is a Single Action Colt Army. This is the finest field gun ever made!" Some could make the argument that this line is a homage to the game Metal Gear Solid, where one of the main antagonists (Revolver Ocelot) proudly boasts about his side iron, "This is the greatest hand gun ever made. The Colt Single Action Army."
The trivia items below may give away important plot points.
During their hike in the Rejection valley, Hiram, Juan and Kelly stumble upon a destroyed wagon belonging to a character named Old Fred. Old Fred was also a character in the original Tremors film. He was a farmer who was among the first to be killed by the graboids along with his flock of sheep and the discovery of his death is homaged in this film.
Michael Gross plays Burt Gummer in the first three films and is a character most famous for his impressive arsenal of weaponry, however in this film he portrays Burt Gummer's ancestor Hiram Gummer, a character who ironically has had no prior experience with firearms; he hires others to do practically everything he has need of.
In the first three films in the series, the three creatures of the graboid life cycle are shown. In this film the baby graboids are new because they jump out of the ground and fly towards their victim, indicating a new characteristic.
All creatures of the previous tremors movies are named differently: graboids, shriekers, and assblasters. However in this film, the baby graboids are named dirt dragons, very differently from the graboids.