Yeah basically new game modes. Rocket Racing is an arcade racer, Fortnite Festival is a rock band like rhythm game, both are entirely independent from battle royale but still integrated into fortnite eco system with skins and characters going between them. This is the metaverse vision that Sweeney never stops talking about coming to fruition.

It wasn't even originally a battle royale game. Before that was a co-op base defense/survival game with resource collection and building elements. Kind of a limited, kid friendly 7 days to die.

Fortnite is like roblox now, it has tons of user generated games inside of it (created using the fornite edition of unreal editor) and multiple epic created games