Diablo 4 was one of Blizzard’s big announcements at BlizzCon 2019. But during the opening ceremony, Blizzard only showed off a little bit of the game. As part of the Diablo 4 panel that followed the ceremony, some of the members of the development team were able to shine a light on some of the game’s other features.

Here are all the biggest differences you can expect between Diablo 3 and Diablo 4.

3 ‘new’ classes

More character classes are probably on the way, but for now, Blizzard has revealed three classes for the game, and even given us a short teaser, showing what each class is capable of.

Druid

Druids can summon animal companions to help do their bidding and take out their foes. They can also use their caster form to control the elements, creating things like tornadoes, and lighting storms. But the most important ability that Druids have is shapeshifting. Through shapeshifting, Druids can transform into a werewolf and even a werebear — those are the two things Blizzard has shown so far. These transformations take place instantly and will let players string together abilities from different forms all in the same fight. The Druid was last seen in Diablo 2.

Sorcerer/Sorceress

This class is exactly the kind of magic user you expect them to be. They can call down massive blizzards to slow their enemies and weaken them, attack with one massive fireball, or call down a rain of them to hurt several enemies at once. This time around, Sorcerers and Sorceresses can even transform into a ball of lighting and rush through the enemies around them. They seem to closely mimic that of the Mage in Diablo 3.

Barbarian

Barbarians have changed quite a bit from their Diablo 3 counterparts. While they’ll still maintain some of the big, brooding abilities they used in the previous game, Diablo 4 turns the Barbarian into a master of any weapon. And to fully show off that mastery, the game will let Barbarians equip different weapon builds all at the same time. This means you could switch between one and two handed builds in the middle of combat, and even equip four different weapons at once.

Skill Trees, Rune Words, and Ability Levels

Diablo 4 will also give players new ways to customize each class they play thanks to the addition of skill trees, Rune Words, and Ability Levels — you can even do some cosmetic customization if you want to this time around. While some of these will be familiar to Diablo 2 fans, the updated versions will give players more options than they’ve had in the past.

Skill trees, based on the limited amount Blizzard showed them off, let players upgrade different aspects of each of their abilities, increasing the damage of the Sorceress’ Blizzard without increasing how much it slows down enemies, for instance. Rune Words, at least in Diablo 2 were special items you could equip to weapons to give them new effects. Ability Levels are exactly what they sound like, ways to make individual abilities a little stronger.

All of these new customization features should combine to make Diablo 4 significantly more flexible. Through different combinations of abilities, armor, weapons, skill tree upgrades, Ability Levels, and Rune Words, you should be able to make your Diablo 4 character wholly unique.

Open World Campaign and Mounts

According to the Diablo 4 developers, they learned a lot from the release of Diablo 3’s Adventure Mode, which came out with the game’s first expansion, Reaper of Souls. Most importantly, they learned that players like to go wherever they want in the game, whenever they want. To this end, Diablo 4’s campaign is now completely open. If you want to tackle the story, start-to-finish that’s fine. But if you’d rather explore the world and complete side quests in various areas, you can do that too.

The new world map is pretty big, so Blizzard is giving players a little assistance in exploring it. New to Diablo 4 are mounts which will allow players to traverse the environment a little quicker than they could on foot. These mounts will also give players the chance to show off some fancy moves, as each class now has a new dismount ability that lets them jump free of their horse — or whatever else they may be riding — and hit the ground swinging.

Darker and more random dungeons

Diablo 4 team is making the whole game a little bit darker. That means scarier enemies, more blood, and less light. Dungeons, the most common environment in Diablo, will now be a little bit darker in Diablo 4. This should make them creepier, but also more unpredictable. Contributing to that, Diablo 4 upgrades the randomness system that Blizzard built into Diablo 3, which should lead to even more varied dungeons.

PVP is back

PVP, the long-promised but never-delivered feature for Diablo 3, is something the team is already promising to include in Diablo 4. Certain areas of the game will be safe while others will be PVP zones where players are free to take each other on if they want to. These areas will all be opt-in, so if you’d rather stick to fighting the minions of hell, that will be an option for you.

Social areas and challenges that include many players

Social areas like towns are also getting a big upgrade in Diablo 4. They’re now places where you can hang out with other players, swap stories, trade items, and inspect builds. You can even gather together in groups in order to take on bigger bosses that exist across the world. During the Diablo 4 panel, the developers showed off a giant boss that seemed to be fighting at least a dozen players at once, making them look almost like a World of Warcraft raid boss.