Uncharted: Golden Abyss is currently only available for the PlayStatiom Vita, although Naughty Dog has hinted at the game possibly receiving a PlayStation 4 remaster.
Golden Abyss is set before the events of Drake's Fortune. Consequently this makes it the first Uncharted entry not to feature the character Elena Fisher.
The first title in the series specifically developed for a handheld, namely the PlayStation Vita.
The first and as of 2016 the only entry in the Uncharted franchise to not be developed by Naughty Dog although they did oversee the project. Golden Abyss is developed by Sony's Bend Studios which specializes in handheld development.
The first Uncharted entry not directed by Amy Henning. Instead John Garvin wrote and directed Golden Abyss.