The violent content of A Fistful of Dollars must have made quite an impact in 1964, I think particularly to those who were familiar with the many television-westerns of those days.
In Sweden the theatrical release of Fistful was somewhat censored, but the film obviously still made an impact.
The poster says:
"One of the strongest westerns ever made!"
"Terribly strong!", "Absolutely not for the faint-hearted!"
"A town where everybody is rich...or dead!"
"A film that strikes hard!"