So what title best fits this film?

[Novecento]

Yes, I don't see much connection between DYS and the 2 OuT films. I always thought that it was very constructed and forced to press DYS as middle part of a triology. And remember it was also a film Leone did not wanted to direct initially.
The re-use of the title works for OuTA, but not for DYS.

And I think that DYS lacks the brilliance of the 4 predecessors, while MNIN has this brilliance, and even if it is a flawed film in parts, it is a much better film than DYS. That doesn't mean that DYS is a bad film. It shows how much Leone has developed his style since FoD, but also the film still shows why Leone did not wanted to direct it himself.

DYS was an underrated film, but now it becomes an overrated film.

Wow, I'd put DYS far ahead of MNIN and consider it a very worthy second installment to the OUAT trilogy. Each to his own I guess...

[stanton]

When I first saw DYS I was disappointed, but since then it has grown on me, but it was then, and it is now still the least of Leone's westerns for me.

I also think that Il mercenario is much better, and even if Companeros is a film with lots of flaws, and in several parts clearly inferior to DYS, I prefer it to DYS for the sheer brillance of some of its scenes.
Compared to the other better known Zapatas is DYS on par with Quien sabe? and much better than Tepepa. And I prefer it to all Sollima films.

[cigar joe]

Well Il mercenario & especially Companero's are lighter fare compared to DYS, Companero's is almost a comedy with a lot of flaws.

I'l Mercenario is probably my favorite Zapata if I define them as an action adventure films.  I'd say that Quien sabe?, Tepepa, and DYS are all more cerebral with DYS the pinnacle of that trend.

[stanton]

Il mercenario is not really a light film.
It is a pretty ambiguous film filled with extraordinary ideas. And it is more complex about its content (the revolution) than it seems at first glance. It works as an impudent actioner as well as a pessimistic and cynical comment on certain leftist ideals. In il mercenario the revolution is always overthrown by the money and in the closing structure of the false endings it changes from optimistic to pessimistic, but still can maintain on the western level of the film an unlikely happy end.

So Il mercenario can be a counterpart to The Great Silence without betraying the ending of The Great Silence, and for thus being a complement to it. Tricky stuff these 2 films.

[drinkanddestroy]

Then how does it fit into this alleged "trilogy"?

it's not a real "trilogy"; nor are the Dollars films, really.

it's 3 films, each with the OUAT title, which some people therefore refer to as a "trilogy." Of course, it is not a real trilogy.

[Novecento]

Just noticed this at the very end of the "Photo" #54 (1972) article here about DYS (my translation):

"Last bummer, the film that comes out just before his on the same circuit has been called 'Il était une fois un flic' by its director Georges Lautner. It's undoubtedly for economic concerns, affirms Leone, they will only have to change the last part of the sign".

[Novecento]

Interesting also how in the 1970 article below the above one (Ciné Revue, N° 53, December 1970), the Italian title of "Giù la testa!" is simply translated in French as "Attention à la tête!" (Watch your head!).

[Sensitive Mule]

I think the OUATTR title is brilliant but that the DYS title probably fits the film's cynical quirky humor better. I use DYS when referring to the film.

[marmota-b]

When I speak about it in Czech, I use the title it went under in TV, Kapsy plné dynamitu, i.e. loose translation of Fistful of Dynamite. However, in English I definitelly use Duck You Sucker, because I love how that saying keeps coming in the film...

Apparently, it's also called "Hlavu dolů" in Czech, "(put your) Head down!" - and now I'm not sure which title to use at all. My mind somehow calls it "DYS", I mean that abbreviation, nothing else...

[drinkanddestroy]

I hate the name "Duck, You Sucker" but that IS the film's proper name in English, even if it was based on Leone's erroneous belief that that was a popular American saying. Nobody I know has ever heard anyone say that phrase.

I really wish it had been called Once Upon a Time... the Revolution. I like to think of Leone as making the  Dollars trilogy and the Once Upon a time trilogy 

[Mr.Cho-Cho]

I agree with the previous poster, I would have gone for 'Once Upon a Time... the Revolution' as part of the second trilogy. I quite like 'A Fistful of Dynamite' though, very punchy. 'Duck, You Suck' is just a bit lame, but I don't mind it when Coburn says it in the film.

[noodles_leone]

Just use the French title, guys.

[Novecento]

Good call

[stanton]

 I think Hlavu dolů sounds handsome too for future worldwide releases.

... and does the film maybe some justice.

[Novecento]

What's really weird is that in Japan three of Leone's films had names that tied them all together, but these three films crossed over the "Dollars" and "Once Upon a Time" trilogies by consisting of the following:

夕陽のガンマン (literally "Sunset Gunman" aka "For a Few Dollars More")
続 夕陽のガンマン (literally "Sunset Gunman sequel" aka "The Good the Bad and the Ugly")
夕陽のギャングたち (literally "Sunset Gang" aka "Duck, you Sucker!")

"Sunset" (夕陽) wasn't used in the names for "A Fistful of Dollars" or "Once Upon a Time in the West".