Few games pack the emotional wallop of The Last of Us. The tale of a grizzled and grieving survivor of a zombie apocalypse reluctantly agreeing to ferry a child to the resistance, only to find that she has given him a new reason to live, introduced a new maturity to developer Naughty Dog, previously best known for its more lighthearted Crash Bandicoot and Uncharted series. It also gave the company a hit: The Last of Us sold more than 17 million copies, all but ensuring the company would invest in a sequel.

At the end of 2016, Naughty Dog revealed that it was working on The Last of Us Part II. And at E3 this week, we got our longest look yet at the game: a 12-minute sequence that blends cinematics and gameplay footage. A special moment at the outset, which finds the game’s heroine Ellie sharing a tender moment at a dance, grimly transitions into violence. Joel, who has become a father figure to Ellie after the events of the first game, is mentioned but never seen.

The first game was grounded in the evolving relationship between Joel and Ellie. So how will the sequel differ? Naughty Dog’s creative director, Neil Druckmann, says The Last Of Us Part II is a tale born of revenge. “The first game, at its very core, was trying to tap into this primal feeling that a parent has for their child. This unconditional love. How do we create a game that captures that? This game tells a very complementary story.”

Druckmann won’t say what exactly inspires the revenge story. But in doing research for the game, Naughty Dog watched documentaries in which revenge played a role, including Paradise Lost, a 1986 film about the murders of three boys in Arkansas. The documentary focuses in part on the rage of the parents of the dead boys, who vow to hunt down and kill the accused killers if they are not convicted of the crime.

“We wanted to deal with this primal feeling,” Druckmann says. ”I don’t know if you’ve ever been in a situation where someone pushed you, or you saw a video of someone torturing an animal, and even for a split second, you’ve thought: I want to make this person pay. And that’s part of the research that we’ve done.”

The world of The Last of Us is still recovering from an infection that wiped out most of humanity and left terrifying zombie-like creatures lurking around every dark corner. Society is still fundamentally unstable, he says, and so the game’s characters are prone to seeking vigilante justice.

“With society broken down, how far would you go for justice?” Druckmann says. “How much would it consume you? How much would it take away from your humanity? How much would it destroy your relationships? Those are all interesting questions for us to explore.”

The Last of Us Part II will evolve from the original in other ways as well, Druckmann says. Ellie can now crawl and jump, dramatically increasing the complexity of the game’s level design. There will be multiple paths through sequences like the one depicted in the E3 demo, he says. The trailer shows Ellie getting caught as she attempts to sneak through a parking garage, but it’s also possible for her to make it out undetected, Druckmann says.

Many key questions about the sequel are still awaiting answers. Zombies, known in the game as “the infected,” are still part of the world. But what new dangers might be found within the game, Druckmann isn’t saying. We also still don’t know what role Joel plays in the new game. He appeared briefly in the game’s first trailer, asking Ellie if she was “really going to go through with this,” but he hasn’t been heard from since. (Incidentally, Ellie’s answer to that question was: “I’m going to find... and I’m going to kill... every last one of them.”)

Most pressingly, we still don’t know when The Last of Us Part II is coming out. Time will tell whether it’s as emotionally satisfying as the original. But from what we’ve seen so far, it certainly looks just as intense.