Well over half of the more than 145 feature films we screened in 2015 were World Premieres. The rest consisted of North American and U.S. Premieres, along with a limited number of non-US Premieres. Our Narrative and Documentary Feature Competition categories consist solely of World Premieres.
So yes, the premiere status of your film is an important factor; and all things being equal, the premiere will get the slot. But it’s not absolute - we make exceptions for films we love. For example, the majority of our 2015 Festival Favorites section was comprised of non-premieres. We generally show about 14 films from the Sundance lineup and 10 films from Toronto. Be sure to read here for advice on applying to multiple festivals and navigating deadlines.
If your film has screened in a theatrical setting to a general-public audience in Austin, including other film festivals (i.e Austin Film Festival, Fantastic Fest, etc), it is NOT eligible.