Marin Mandir said this is his favorite of all his films made from the year 2009 to 2013. The record stood for five years, until it was topped by Karolina's Perfect Day (2018) which the director considers his finest movie of his own of the decade.
During principal photography, all the scenes involving Monika Kis were filmed first. All her scenes were filmed in three days, while the crew then went on to film the rest of the film the following two weeks.
Marin Mandir thought that the chances of Monika Kis accepting the role would be less than 5 %, but was surprised when she read the script, liked it and accepted to star in the film. She traveled 310 miles from Novi Sad, Serbia to Zagreb, Croatia for the film.
In Mandir's 2012 film, Facebook Double (2012), the main protagonist is mistakenly accused of forming a friendship on Facebook with Monika Kis. Coincidentally, Kis starred a year and a half later in this Mandir film.
Along with Reptiloid (2013), a science-fiction film, 'Nikolina & Tomislav, Nikolina & Tomislav', a romantic drama, forms a double-bill of first two serious films directed by Marin Mandir. Previously, he only directed comedies. Coincidentally, even though the principal photography for 'Gmaz' was in September 2012, both films were completed in almost the exact same month: 'Gmaz' in July 2013 and 'Nikolina & Tomislav, Nikolina & Tomislav' in August 2013.