Set in 1971–1988 Calcutta, Gunday is a story about two best friends and outlaws, who fall in love with a cabaret dancer, which causes rivalry and misunderstandings between them while a police officer tries to take advantage of this situation to eliminate them.

Zafar conceived the film, which was the last to be narrated to founding patron Yash Chopra, as an amalgam of stories he had heard from his father as a child about the effects of war-caused immigration and the Mafia Raj's illegal marketing of coal.

He wrote the film as a tale of the consequences of the struggle of two outlaws against the system, using his father's stories as a backdrop for the characters.

The soundtrack was composed by Sohail Sen, and the lyrics were penned by Irshad Kamil, while Julius Packiam composed the background score, taking over Sen's duties from Zafar's debut, Mere Brother Ki Dulhan, eventually becoming a regular collaborator.

The film won Best Action at the 60th Filmfare Awards and was nominated for Best Choreography for the song "Tune Maari Entriyaan."

[6][7] Zafar decided to set the film in Calcutta, since he felt the story suited the city's political climate.

[6][7] He believed that the films' portrayal of the conflict between right and wrong gave him an understanding of life as a child, which he used in the script.

[6] In an interview, Zafar said that the film depicted the consequences of the outlaws' struggle against the system: "If someone is deprived of basic rights, there will certain youth who will be disillusioned and go over to the dark side.

[12] Chopra described her character Nandita, the cabaret dancer, as a girl next door who acts as the main catalyst for driving the story further and igniting the conflict between Bikram and Bala when they both fall in love with her.

[15] For Khan, who had mostly performed in niche dramatic films, Zafar made his character a lot more flamboyant and mainstream.

[19] While filming a song sequence, Singh injured himself after falling from a height; he suffered a gash on his cheek.

[21][22] One of the early filmed scenes included a dramatic Durga Puja sequence under the Howrah Bridge with a crowd of 1000 people, for which a huge pandal was created.

[24] The song "Tune Maari Entriyaan" was shot across various locations, including scenes at the streets of Calcutta High Court, Dalhousie and Dakshineswar Kali Temple.

Additionally, a small part of Calcutta was recreated at the Film City in Mumbai, which included places with signboards in Bengali, CPM flags, yellow taxis and the iconic Metro Cinema.

[4] The cabaret dance number "Aslaam-E-Ishqum" featuring Chopra was filmed in early July over six days on a set created in Mumbai.

[6] A huge coal mine set was erected at the Yash Raj Studios, where the four principal actors filmed the action scenes in July.

[28][29] Zafar also revealed that fifteen days worth of shooting was left for the film, which was scheduled to occur in Kolkata and Raniganj.

[32] The lyrics for the Bengali version of "Tune Maari Entriyaan" were written by Bappi Lahiri and Gautam Susmit.

[32] The vocals were performed by Javed Ali, Shadaab Faridi, Bappi Lahiri, KK, Neeti Mohan, Vishal Dadlani, Arijit Singh, Neha Bhasin, Shahid Mallya, Altamash Faridi, Sen, Kinga Rhymes and Monali Thakur.

[38] The teaser trailer of the film was released on 22 November 2013 along with Gori Tere Pyaar Mein, and received a positive response, with India Today calling it "action-packed" and "promising".

[48] An article published in The Wall Street Journal wrote that "to claim that India's participation alone brought about independence, as the film does, is incorrect [...] Bangladesh was born because Bangladeshi fighters had been battling the larger and better equipped Pakistani military for months.

[49] Irate Bangladeshis launched a social media campaign with the hashtag "GundayHumiliatedHistoryOfBangladesh" on Twitter, asking people to bury the film on the Internet Movie Database (IMDb).

[60] Taran Adarsh of Bollywood Hungama gave a rating of 4 out of 5, calling it an "entertainer" and writing that the film "has an attention-grabbing premise, well-etched-out characters, high-octane drama, is generously peppered with vibrant songs and energetic action pieces, boasts of defining performances from the principal cast.

"[62] Mohar Basu of Koimoi also gave it 3.5 out of 5, calling it a "must watch" for "the oomph and bombastic dialogues", and praised Zafar's direction, writing that "the execution is what makes the fast depleting story hold its ground.

"[63] Mint gave a highly positive review, calling it a "spectacular tribute to 1970s' Hindi cinema", and wrote that it "moves at a satisfying clip from the beginning to the end.

It's formula food for the present day, spiced with flamboyance, a fair sense of rhythm that occasionally slackens during the 153-minute running time, and a clear understanding of the meaning of popular entertainment, Hindi movie style.

"[65] Writing for Hindustan Times, Anupama Chopra gave it 3 out of 5, calling it "an unabashed love letter to the 1970s" and writing, "Though the story is set in the 1980s, Zafar recreates a classic '70s vibe with punchy dialogue-baazi, scenes designed to make you applaud and a relentless background score by Julius Packiam that underlines every beat just in case you missed a high note.

"[67] Daily News and Analysis gave it 2 out of 5, noting that every critical conflict in the story was flaky and the bromance was a letdown.

[68] Sukanya Verma of Rediff.com also gave it 2 out of 5, criticising the script, which she thought was full of "silly loopholes, annoying clichés and glaring superficiality", writing that "No matter how hard Zafar tries to create an action hero [...] he fails to substantiate it with charisma that goes beyond surface value.

[70] Raja Sen of Rediff gave the film 1 out of 5 stars and said, "Director Ali Abbas Zafar has directed a monstrous film, one with a repellent 70s-set storyline that makes no sense whatsoever, and a cast who should all hang their heads and offer up a minute's silence for assaulting their respective filmographies.