Big-Lipped Alligator Moment: The entire subplot of the couple who keep getting harassed by the cops as they make out, which never comes close to having a point. It was put in purely to provide a role for the actress, who was going to play one of the Master's wives but couldn't because she broke her leg. It also gave the actor playing the boyfriend more of a reason to be there. (He was originally a stunt double and nothing else.)
And he is neither a satyr (the deformed legs are a variant of the usual hunchbacked henchman, which was thought to be too clichéd even in 1966) nor does he have cloven hooves (the non-MST3k version shows him wearing shoes quite clearly).
Also, that is John Reynolds doing Torgo's voice, despite what was believed for a long time. And Michael and the Sheriff are not voiced by the same guy. They did dub themselves.
Some sources have assumed that Robin Redd (who plays one of the Master's wives) is actually character actress Mary-Robin Redd due to their similar names. But Mary-Robin Redd was already an established stage and television actress by this time, whereas the film's Robin Redd (like the Master's other wives) was a model from El Paso.
The Master is an undead, immortal occultist who serves the evil god Manos by happily performing human sacrifices for his deity, keeping a harem of wives which he disposes of as he sees fit. Having killed his first servant Vassago for stealing one of his wives, the Master later brainwashes a man named Torgo to act as his newest servant. When a small family is later lured into his Lodge by Torgo, the Master kills the family dog, before chopping off Torgo's hand for touching his wives in their sleep. He later forces both Michael's wife Margaret and his little daughter Debbie to become his new brides, with Michael himself being brainwashed into becoming the new Torgo. Keeping people's spirits in a perpetual limbo, the Master's spirit continues to loom over the Lodge, brainwashing more women to become Manos's brides, having forced Debbie to become his replacement as she continues to sacrifice those in the name of Manos.
The Rise of Torgo: Manos himself, God of Primal Darkness, is the instigator for everything that happens in the trilogy. Having chosen The Master to become his immortal slave, Manos has him carry out his desires for Human Sacrifice, having him brainwash women to serve as the wives of Manos. After the Master kills his servant Vassago, Manos chooses the innocent Torgo as his new servant, brainwashing and threatening him with 1,000 deaths of darkness should he go against him.
Cult Classic: Yup, a film about a cult has cult fans. It has quite a passionate fanbase due in no small part to it being laughably awful.
Designated Hero: Mike, who never does anything to make you sympathize with him. He orders Torgo around, ignores his wife's constant pleas, and continuously calls Debbie "my baby" like Margaret had nothing to do with her.
Fridge Horror: It's probably best to assume that Harold P. Warren didn't intend for the characters to be the same ages as their actors. Otherwise, it would mean Michael is 43 and his wife is only 19 - and they have a seven year old daughter. Given that Michael is already a Designated Hero, this would just make him seem slimier.
They Wasted a Perfectly Good Plot: The concept for the film is actually not a bad one. You're lost in the desert, and the only person willing to take you and your family for the night is twitchy yet well-meaning, except when he randomly begs you to leave. It gets worse from there. The ending in particular could have been effective and chilling in more competent hands.
Debbie was dubbed over by someone who clearly wasn't a little girl. The little girl playing her cried when she first heard the dub, and one can hardly blame her.
Torgo was intended to be an example of this, but due to various factors, comes off as more of a creepy Cloud Cuckoolander.
Unintentionally Unsympathetic: Margaret was probably supposed to be The Woobie, based on how much bad stuff happens to her and how she keeps crying, but, due to a combination of terrible acting and generally coming across as way too whiny and helpless (such as spending most of the time Torgo is bothering her crying out to Mike for help instead of making any attempt to escape), she's just annoying instead.
What an Idiot!: Yes Mike, it's a good idea for you and your family to stay with the creepy bearded guy in the creepy lodge in the middle of nowhere. That'll definitely work out for you.
Well, director Hal Warren was by all accounts perfectly lucid during the production, but Torgo's actor John Reynolds was said to have used various recreational drugs such as LSD, explaining his various twitchy behaviors and mannerisms on-screen.
The female vocalist who sang "Love Inside This Magic Circle" and "Forgetting You" (Nicki Mathis) remembered the film's composers acting weird during the recording session, and suspected they were on drugs, which would explain the more bizarre elements of the score.
Due to his speech problems, hobbling gait, and the way Michael and The Master treat him like crap, Torgo manages to fall into this. He counts as a Jerkass Woobie as well, since he's a bit of a groper and a pervert towards Margaret.
The Master's Wives are halfway there, with the implication being they are held against their will as the Master's sex slaves and there are hints that Torgo molests them during their hibernations. However, they appear to be extremely jealous and petty of each other and the new guests. Not to mention, killing Mike was their idea, not the Master's.