With six years between the original release of The Last of Us and the impending launch of The Last of Us Part 2, Naughty Dog has had a lot of time to make significant changes to the series. Part 2 revamps the original game's systems with alterations ranging from small tweaks to big twists, and just about everything fans will remember has been adjusted in the sequel.

We recently got hands-on with The Last of Us Part 2 and saw first-hand all the new and altered things coming to the game. They range from new enemy types and challenges to changes to how you'll unlock new abilities for Ellie and modify your weapons as you guide her on her quest for revenge. Here's everything we've seen so far that's changed between The Last of Us and Part 2, to help you better prepare to return to Naughty Dog's post-apocalyptic world.

While you're at it, check out the two NSFW Easter eggs we found during our play session.

Ellie Can Jump, Climb And Crawl

As compared to Joel, Ellie is a much more mobile and agile protagonist who's better able to change positions in combat and get herself out of trouble in stealth. The big additions on the movement front are Ellie's ability to climb over things and crawl underneath them. There's a dedicated jump button, so rather than search for a convenient ladder any time you need to go up, Ellie can jump and haul herself up onto objects, provided they're not too tall, adding a lot of verticality to her capabilities. She can also drop to her stomach and crawl, allowing you to slip under cars or doors. You'll use these abilities for solving puzzles, but they're also essential in combat and stealth to help Ellie lose her pursuers.

There Don't Seem To Be Ladders And Planks

We got the impression from our hands-on session that Naughty Dog has reworked the fundamentals of puzzles you'll solve in Part 2. Instead of finding planks of wood everywhere to make bridges over gaps, and ladders to get you over walls, you'll need to make use of Ellie's movement abilities to find pathways forward. One thing that is returning from The Last of Us, though: dumpsters. At least once, you'll be pushing a big metal trash container around to help make a step you can climb up to reach a higher place.

Visibility Matters

The crawl ability isn't just for slipping through holes or under objects. It's also useful in stealth situations, as Ellie can crawl through tall grass to reduce both the sound she makes and her visibility. Enemies can't see Ellie at a distance when she's crawling through grass, although they will spot her if she gets too close. Going prone gives you a chance to move from position to position without getting spotted, though, as long as you're careful. It gives you a lot more options when you're trying to stay hidden, and in combat, it can allow you to lose enemies and reposition yourself to flank them.

There's A Dedicated Dodge Button

Also adding to Ellie's repertoire of moves is a dodge ability, which is tied to tapping the sprint button. The dodge allows Ellie to slip by attacking infected or get clear of incoming melee strikes from human enemies, allowing her to follow up with counterattacks. Dodges can also help you shake an enemy's aim. In general, Ellie's agility helps keep her alive, and you'll need to get good with the dodge ability to survive some of the more harrowing fights in the game.

The Shambler Is A New Infected Enemy

In Part 2, you'll see a lot of the same infected enemies you're used to from the first game, including Runners and Clickers. The hands-on session we played also added a new enemy called the Shambler. These big infected are hard to take down, absorbing a lot of damage. They're mostly dangerous by proximity, though--they spray deadly acidic clouds in all directions when they take hits, when they draw near to you, and when they die. It seems the best way to deal with them is to set traps or blast away at them from afar (we found you couldn't stealth kill them, at least during our demo); if they corner you, it's all over.

Human Enemies Now Bring Along Attack Dogs

The other new enemies we saw in Part 2 were attack dogs, which joined the humans to hunt Ellie through one of the levels we played. Dogs change up a lot about enemy encounters when they're present. First, they can smell Ellie, which means you're not safe if you're out of sight or behind cover. Dogs who cross Ellie's trail will pick up her scent and follow it back to where she is, which means you'll need to keep moving a lot more in Part 2, even when sneaking. You can lose dogs by throwing a bottle or brick to distract them, or by keeping on the move long enough for them to lose track of your trail.

In combat, dogs are a different kind of major threat. They'll rush you, attempting to knock Ellie down and tear her apart. They're quicker and lower to the ground than other enemies, which can make them tougher to shoot and more difficult to fight off with melee weapons. They're also very good at distracting you while their owners finish you off with firearms.

Listen Mode Includes Your Scent Trail

The good news is, you won't be completely surprised when a dog starts tracking you. Part 2 telegraphs these moments with enemy dialogue so you'll know when a dog has picked up your trail. You can also see the trail, and the path it'll lead the dog on, when you activate Listen mode, Ellie's ability that allows you to see enemies through walls and other objects. Listen mode has undergone some other tweaks, too, though; it's less effective and more obscured at longer distances, making it tougher to pick out enemies that Ellie can't hear as well.

All The Enemies Have Names

One of the big themes of The Last of Us Part 2 is how you can lose your humanity in the fight for survival and the quest for vengeance. Kill animations are even more brutal than they were in The Last of Us to highlight just how intense and terrible Ellie's fight for her life can be. Naughty Dog is selling the horror another way as well. Each of the human enemies in the game has a name, and you'll hear them using one another's names as they coordinate to search for you or attack you. Kill an enemy, and their friends will often scream out their name in anger and anguish. That goes for when you kill dogs, too (and you'll kill a lot of them, it seems). If that sounds unsettling, that's what Naughty Dog says it's going for--expect to feel bad for killing enemies, even though they're also trying to kill you.

Encounters Are Bigger, With More Options

In the sessions we played, we noticed that Naughty Dog has greatly expanded on the size and scope of enemy encounters and level design. Expect to come across locations that mix together interiors and exteriors, with plenty of holes, doors, broken windows, and narrow passageways that will allow you to slip between positions. Ellie's movement abilities, and the new capabilities of enemies to find her, will push you to move around a lot more, whether you're sneaking or fighting. Part 2 provides a lot more options to make movement viable, giving you plenty of places to hide behind and shoot from. You can also pull of plenty of contextual attacks, like using objects in the area against your enemies so you can open them up to killing blows.

Enemies Are Smarter, But That Can Make Them More Predictable

Like just about everything else in Part 2, Naughty Dog has amped up enemy AI to make the human survivors you fight seem more human. They now have a new awareness state between having no idea where you are and knowing exactly where you are, which co-director Anthony Newman called "vague knowledge." If you kill an enemy from a hidden position with an arrow, for example, their nearby friends will notice and intuit vaguely where the attack came from. The enemies will then use that information to try to track you down, but they won't know your exact position yet. You can use that to your advantage; with the enemies acting more like real people, players will better be able to anticipate where they'll go and what they'll do.

Allies Are More Helpful

Enemies are smarter in Part 2, but so are your allies. Of the two levels we played, the first featured Ellie on patrol with love interest Dina, and the pair worked together to clear out infected from an abandoned town. Where 14-year-old Ellie could contribute in a battle in The Last of Us but mostly stayed out of the way, Dina is a more active fighter who's capable of executing her own silent takedowns of enemies. Newman also said Dina will contribute in a battle with her gun, and her bullets do as much damage as Ellie's (unlike the shots of your pals in, say, Uncharted 4). You can use allies' help to your strategic advantage, too--if Dina puts a few shots into a runner infected while you're watching, for instance, you'll know you will only need one or two more shots of your own to finish it off.

Upgrades Have More Meaning

Like in The Last of Us, you'll upgrade Ellie's abilities by finding and using Supplement pills you scavenge from the game world. Naughty Dog has tweaked that system, though, and Ellie had several skill trees during our session that unlocked new abilities. Grabbing one upgrade might open up new crafting abilities, for instance, or make her quicker while crawling. You can use the upgrade system to tailor Ellie's capabilities to your playstyle.

Gun Mods Also Customize Your Playstyle

In addition to upgrading Ellie, you'll also upgrade her guns, using workbenches and machine parts you find out in the world. Upgrades to guns tend to focus on enhancing their capabilities and changing them pretty significantly--we added a scope to our hunting rifle that greatly increased its range, for instance, and amped up our pistol to increase its magazine and reduce its sway. Newman said Naughty Dog wants your guns to feel like an extension of your character customization, so expect to be able to pick upgrades that fall in line with your personal play style. Workbenches also come with new animations to make them feel less like big menus, with Ellie quickly disassembling her guns and adding new components as you upgrade them.

Training Manuals Can Open Up New Skill Trees

Training Manuals are back, and you can find them in-game to teach Ellie new skills. They seem to be a bigger deal in Part 2. We found a manual about archery soon after Ellie acquired a bow that opened up an entire archery-dedicated skill tree she didn't previously have. It seems that, if you're diligent enough, you'll locate manuals in the game that can give you access to whole new sets of abilities.

You Can Make Silencers For Your Guns

One big new craftable item: a disposable, improvised silencer. You'll need to unlock the ability to craft them from Ellie's skill tree, but they make sneaking around and taking down enemies a lot easier. The silencers are made from plastic bottles, so they only last for a couple of shots, but when you're trying to stay quiet, they're a huge help.

Never Craft Another Shiv

Good news: You won't be crafting shivs from bundles of broken scissor parts anymore. Though they were pretty essential for stealth kills in The Last of Us, especially against the extremely deadly Clickers, the items are completely gone in Part 2. Instead, Ellie carries a switchblade that allows her to execute relatively quick stealth kills against humans and infected, including Clickers. The knife isn't enough to take down every enemy you encounter, though--we tried to use it on one of the bigger Shamblers to no avail.

Actually, There's No Multiplayer

Naughty Dog revealed during the preview session that, unlike The Last of Us, Part 2 will not include a multiplayer mode. That's a change from what it has previously said, but according to the studio, it's focusing solely on its single-player story mode. That'll likely disappoint some fans, but it makes sense--writer Neil Druckmann said during the event that The Last of Us Part 2 is the biggest game Naughty Dog has ever made, in terms of length, scope, and ambition.