Hordes. It had to be hordes.

Uncharted 4 may prove to be Naughty Dog's final installment in the Uncharted franchise, but don't take that to mean that the developers are done expanding upon their popular finale quite yet.
In a post on their official website, Naughty Dog has announced that Uncharted 4 will be getting a brand new co-op mode called Survival as part of an upcoming update. Just to prove to you that this isn't some fantasy we've concocted in an effort to inspire Naughty Dog to give us all more Uncharted, we've included the release trailer for this new mode below:
Survival will be instantly familiar to anyone that has played a horde mode in the last 10 years or so. In it, up to three players can participate in a wave-based fight featuring various enemies from the series. At first, it appears you'll be fending off rather disposable mercenaries, but things quickly escalate to a point that includes demon pirates and other super powered baddies. Furthermore, every 10th wave will be highlighted by a unique boss fight.
So far, Survival sounds similar to Arena co-op mode featured in Uncharted 2 and Uncharted 3, but it does feature a couple of twists on that old formula. The most intriguing of these variations is a mechanic that adds specific objectives to certain waves. While some are combat-based like an objective that requires you to only use pistols during that wave, others will see you tasked with collecting all the treasure spread throughout the area before the wave concludes.
Additionally, players will be able to level up through the course of their play in order to unlock new abilities and weapons that will, hopefully, allow them to compete in the late stages of Survival.
There's no official release date for Survival aside from a vague December release window, but those attending PSX next week will be able to try the new mode out for themselves at the Uncharted booth.