The first movie has been accidentally released into the public domain upon its release. There are other films published under the Trinity brand but only these two are true to canon. The rest are earlier, more serious and grim films also starring Hill and Spencer but in different roles.
Badass Family: We only see Trinity and Bambino's parents for a short time, but it quickly becomes apparent where they got it from.
Bloodstained Glass Windows: There is no actual blood spilled, but the final fight scene in the second movie takes place inside a monastery. With the monks participating.
Cut a Slice, Take the Rest: In the beginning of the first movie, Trinity drifts into a bar to have a meal after a long journey. The bartender gives him two scoops of beans. However he eats from the pan and proceeds to empty it under the disgusted looks of the others.
Faux Affably Evil: The Big Bad of the first movie, Major Harriman, is cruel enough to want to massacre a settlement of religious pacifists (women and children included) just to pasture his horses, but he is also witty, cultivated and a very polite Southern Gentleman. He even tips his hat to the heroes as he rides off in defeat.
French Cuisine Is Haughty: In the second movie, the two borderline-illiterate outlaw brothers suddenly find themselves really rich, buy smart suits and go to an expensive French restaurant. Hilarity Ensues.
The Gunslinger: Trinity is known as "the Right Hand of the Devil". Appropriately, Bambino is "the Left Hand". In case you haven't figured it out, he is left-handed.
To the point that the German dub was given the title "Die rechte und die linke Hand des Teufels" (The Devil's right and left hand).
Gun Twirling: At one point in the second movie, Trinity manages to bitch-slap a guy fifteen times, twirling out a gun to his face with the same hand, to and from its holster. Before said guy even has a chance to reach out for his own! To give an idea of how fast he did it, when done at full speed each slap was timed at just under two seconds!
Implacable Man: Bambino is unstoppable in a brawl. Trinity, who is quite fast and hits very hard, accidentally punched Bambino in the first movie, which only garnered an annoyed look from him. Trinity immediately apologized and slunk away.
Trinity has quite godlike powers with his revolver.
As is Bambino. At one point, the Big Bad of the second movie is attempting to passively threaten the brothers. Trinity quick-draws, fires from the hip, and extinguishes a cigarette one of the Mooks was smoking. Then Bambino pulls the same trick to relight it.
Offhand Backhand: You have read the above above about Trinity's gun skills, right?
The Promise: The major plot driving force in the second movie is Bambino's promise to look out for Trinity to his father, who was actually only faking his own death.
Red Baron: Trinity is known as "the right hand of the Devil" for his quick-draw and his aim. Bambino is known as "the left hand of the Devil" for the same reason (their names match their revolver hands, naturally).