Fernando di Leo was an interesting filmmaker. As a screenwriter, he left his traces in any possible genre, including many spaghetti westerns, even many famous spaghettis, like Navajo Joe, The Return of Ringo, Massacre Time or Long Days of Vengeance. But when he became a director, he never made a western and made a lot of mafia movies instead. His heroes were mostly gangsters or vigilantes, when he made a movie about a cop, he was usually a corrupted one.
Naked Violence (1969)
All I know is this one is more of a social drama perhaps? Co-starring Nieves Navarro under her Susan Scott alias.
Slaughter Hotel (1971)
At the beginning of his career, he tried to make a giallo, and... didn't succeed. This movie is mostly boring and pornographic. Rosalba Neri is hot as hell in this, but we didn't need to see her body double touching herself. Klaus Kinski is useless in it.
Caliber 9 (1972)
This is where the real Fernando di Leo begins. A mafia movie with a great cast (Gastone Moschin, Barbara Bouchet, Mario Adorf, Lionel Stander, Frank Wolff, Luigi Pistilli etc.), good story and unexpected twists. Perfect score by Luis Bacalov and Osanna, amazing opening sequence.
The Manhunt (1972)
Second film of his sort of trilogy, this time starring Mario Adorf as a falsely accused pimp, who has to hide from mafia killers. And those killers are Henry Silva and Woody Strode. Bad times for Mario... bad times for almost everybody, mostly the women - and what women! Luciana Paluzzi, Femi Benussi, Sylva Koscina... Great funky score, this time by Armando Trovaioli, great action sequences. The chase in the middle of the movie is insane.
Boss (1973)
Final film of the trilogy, but not as good as the previous two in my opinion. Henry Silva stars as a cold-blooded killer, who kills everyone in his way to the top. Richard Conte is the mafia boss, Gianni Garko is a corrupt policeman.
Shoot First, Die Later (1974)
Again a weaker one, first of Di Leo's collaborations with Luc Merenda. Merenda plays a cop here, but a cop working for the mafia. Richard Conte is here again, as a lawyer this time, and we also get Di Leo's favourite actor, Vittorio Caprioli, playing a deaf old guy, who becomes a witness of a crime, and therefore dangerous for the mafia. Delia Boccardo is Merenda's girlfriend, so we know she won't meet a good end here.
Kidnap Syndicate (1975)
Merenda again as a father, whose son is kidnapped together with a son of a rich businessman played by James Mason. When Mason refuses to pay the ransom, the poor child is killed in order to force Mason to pay. Merenda gets in a rage, but... the second half is not such a riot as we would expect from the director of Manhunt. Vittorio Caprioli is back as the policeman.
Loaded Guns (1975)
Poliziesco / sex comedy starring Ursula Andress! Not a bad one though. Yes, it becomes really silly and there are moments when Andress' body plays the lead, and the final fistfight is really silly and feels out of place. But a fun movie.
Nick the Sting (1976)
To be honest, I stopped with Di Leo in 1975 so far, so just quickly to the rest. This one stars Merenda again, paired with Lee J. Cobb. All I know about it.
Mr. Scarface (1976)
Jack Palance as a mafia boss in a eurocrime comedy. Seems so.
Blood and Diamonds (1977)
Claudio Cassinelli takes the lead here, Barbara Bouchet returns as a gogo dancer once again. Martin Balsam is in it as well I think. And Vittorio Caprioli again.
To Be Twenty (1978)
A sex comedy that turns into a horror in the end.. Sex comedy starlets Gloria Guida and Lilli Carati starring. Caprioli again co-starring.
Madness (1980)
Joe Dallesandro as a criminal on the run in this movie. I think so.
Killer vs. Killers (1985)
I think this is di Leo's last movie and he didn't end with anything else than a gangster movie with Henry Silva. He made an action flick with him the previous year as well I think.
Well, seems like apart from crime movies and sex comedies and one sex drama Di Leo really didn't do any other genres. But that kind of compares him with Sergio Leone, as the master of the poliziotteschi genre. Not that his movies were as great as the Sergio Leone westerns,but he really concerned to one genre, like Leone with westerns or Dario Argento and Mario Bava with gialli and horror. Other directors made most of the genres. These did their stuff.