In Germany there are some interesting, similar remains of this honour and duel system: within the academic fraternities. There are also some, that legitimately have fencing duels with sharp blades (sharp, not pointed, they cause non-lethal wounds) about honour matters. To be competent, they get trained within their fraternity (if it is one of the fencing ones), and are only allowed to duel with someone from another fencing frat. They also have a second each to assist them during the fencing, comparable to the guys that used to handle the guns for the duelists, and a neutral referee. When two people from a fencing frat meet, they will have a quite different behaviour compared to meeting others.
The remarkable fact about this whole honour and fencing business is, that it is fully covered by the law, in a country that has very strict laws about weapons of all kinds. And yet it is possible to challenge someone for taking your seat in a theatre to a duel with sharp steel blades, provided you and the other are both members of a fencing frat. You will not be able to kill anyone, but in those duels (Mensur) severe wounds to head and face can occur.
If we take both positions 'gentleman' and 'vendetta' and take a look at our general medias, what approach is presented more often?
Is there a really good example of a 'gentleman'-driven plot?
After some thinking I came to HERO from Zhang Yimou: the whole plot unravels about the nameless one, and how he carefully chose his path to get close to the king. To commit a deed of great honour by not killing him, and facing his own death as an assassin, to be buried like a hero. The honour to prove a point, knowing this can end your life.
Maybe we should not call the game 'Dishonored' but 'Vendetta'... but then again, that was a game from System Three I used to play on my C64