As expected, Epic released Fortnite version 11.31 this week. In addition to Winterfest and various bug fixes, the update also adds ‘Battle Lab,’ a new way for players to create their own battle royale islands. This new feature differs from Playground — rather than creating worlds and fun games, players are given the ability to play battle royale games with their own rules.

The distinction between Playground and Battle Lab may not be immediately clear. Whereas Playground gives players access to the complete battle royale island, Battle Lab enables them to actually create battle royale games. Players can fight each other in Playground but the experience differs from a proper battle royale game.

Players can create their own battle royale mode for up to 15 of their friends; there’s also the option to set matchmaking with default options for a public lab. Players are also given the ability to choose which ‘combat scenarios’ they want using Bot Grenades, to adjust fall damage and gravity levels, and choose from various Limited Time Mode pools.

The options make it possible to experience a battle royale game in entirely new ways — you can, for example, play a proper battle royale game that includes low gravity, forcing players to think carefully before they decide to jump. Playground, meanwhile, now exists within Creative, which makes sense considering that Playground has also been intended for creative uses.

Battle Lab aside, the game update has added a number of bug fixes, including ones for mobile devices. Players can once against join parities using a controller, see a properly synced ‘Item Shop’ countdown timer, and enjoy better overall game stability. As well, Epic says that hitching and FPS issues should be improved for mobile players.