Travel Rivellon With Three Friends

You venture through Rivellon as a party of up to four, and the store attaches one sharp condition to that arrangement.

Only one of you becomes a god

The store says you can venture as a party of up to four, but only one of you will have the chance to become a God. That single sentence changes how a co-op run feels, because the group is co-operating towards an ending that only one of its characters can actually have.

Companions are relationships, not slots

Gathering your party includes developing relationships with your companions, and the six origin characters each bring their own backgrounds and quests with them. Treating them as characters rather than as party slots is what the store is selling here, and it is also what makes the choice of who to bring meaningful.

Play alone or beyond Rivellon

You can explore alone or in a party of up to four players in drop-in/drop-out cooperative play, with online and split-screen multiplayer and full controller support. Beyond Rivellon there are the PvP and Game Master modes, plus fan-made campaigns and mods to download from Steam Workshop, and the Definitive Edition pushes the whole thing to 4K.

The characters you bring are covered in choosing who you are. The fights you bring them into are covered in using the environment as a weapon.