Trivia: Total Recall was based on a 1966 short story from pulp-fiction writer Philip K. Dick called "We Can Remember It for You Wholesale". He also wrote other mind bending novels on which futuristic films like 'Minority Report', 'Blade Runner', 'Impostor', 'Screamers' and 'Paycheck' were based. Like many movies, the plot is only loosely based on the original story. In this case, the movie follows the original story up to visit to Total Recall after which the two diverge completely.
Trivia: Originally, Helm's death was more graphic. Thumbelina had actually gutted Helm from crotch to sternum with the Bowie knife. To secure an R rating, the filmmakers had Thumbelina stab Helm in the stomach instead. During the final battle between Quaid and Richter, Richter's arms are cut off, and he falls to his death. However, the comic book sequel "Life on Mars" resurrects Richter with a pair of robot-like prosthetic arms.
Trivia: Kuato's voice saying 'open your mind' was sampled in early 90's Italian electronic/dance group Usura's European hit of the same name.
Trivia: The burly miner Quaid encounters on the train to the Mars hotelstry is Mickey Jones, who performed Michael Ironside's partner Chris Farber in the series "V". Ironside also wears the same kind of clothes he did as Ham Tyler in that series. (00:48:00)
Answer: It depends on whether you choose to believe the events of the film are real or in Quaid's lobotomized brain. If the events are real (i.e. Quaid is actually Houser with his memories blocked) then Harry is from the agency and is there to make sure Quaid doesn't say or do anything that would potentially break his memory block (like going to Recall). If you believe everything is in Quaid's mind after he goes to Recall, then Harry really was just his friend.