The movie, which is released in the UK this month, is about three young Arab women sharing an apartment in the Israeli city of Tel Aviv.
Away from the traditions of their families, they find themselves "in between" the free lives they're aspiring to lead and the restrictions still imposed on them.
"It's naive to say, 'no I didn't expect any comeback' when I wrote it," says Hamoud, "but I didn't know how big it would be.
"I knew when I started to write these characters that it could not be passed by, but I did not expect the extent of the reaction."
Her characters are: Nour, who seems to be heading for a respectable marriage, but her fiance is exposed as a religious hypocrite; Salma, who dreams of being a DJ and is unable to tell her family she is gay; and Laila, a successful lawyer, who hopes for a partner who is as liberal and independent as her, and is disappointed.
The film is also set within the Palestinian underground scene (a group of young Palestinians living in Israel who are using music to forge a new cultural identity for themselves) and features an electronic soundtrack from local DJs.
Hamoud was born to Palestinian parents in Budapest in Hungary, but is now a resident of Jaffa in Israel. Her first short film, Sense of Morning, was set in the Beirut war of 1982, but believes In Between "is every bit as much a political film".
That would appear to be borne out by the reaction, particularly in the conservative Arab town of Umm-al-Fahm in northern Israel, where one of the characters, Nour, comes from. According to Hamoud, it was the mayor here who first declared her film "haram", or forbidden.
"Palestine has a young cinema and there are not a lot of genres here yet," she explains. "I think there was actually a lot of confusion here when the film first appeared as to whether it was a documentary or a fiction film.
"I think some people watching it actually thought it was real life, and this is when the local leaders said they were ashamed of it, and started to go against the movie, and started talking about closing the cinemas down where it was playing.
"So my film was declared "haram", the fatwa issued, and we started getting death threats. There was a very violent atmosphere for a couple of weeks that was pretty scary.
"But you know, there is no such thing as bad publicity," she adds. "More people started coming to see the film to see what all the fuss was about, and it ended up playing at cinemas for months. I've had great reaction from both men and women."
In Between has since been nominated for 12 Ophir Awards - Israel's version of the Oscars, while Hamoud was given the best young talent award by the Women in Motion movement at the Cannes Film Festival this year, with Isabelle Huppert calling the three women characters of the film "heroines of our time."
Maysaloun Hamoud says that while the three women she wrote weren't necessarily representative of her or her own friends, "they do represent the things that we have never talked about in our society before.
"All three characters represent huge amounts of invisible women, women who have never had their voices raised before in cinema from this part of the world. Finally, the film has made people talk about it and I'm glad."
In Between is released in the UK on 22 September 2017.