Epic Games is hard at work on its upcoming sandbox building action game, Fortnite. You might recall that we featured the game on our May 2014 cover. Now, we’ve got a new look at the different characters and gameplay elements that make up the free-to-play title.

The thirteen-minute video shows off the Defend the Fort mode. Players are tasked with building up their fort and, when ready, closing a gate that will summon the storm and a horde of enemies. 

The enemies, known as Husks, can be defeated in direct combat or by laying traps (similar to Orcs Must Die). Each of the three classes offer different specialities, but aren’t limited to a set play style. You can equip your melee-focused ninja with ranged weapons if you prefer, or perhaps you’d like to give your gun toting commando a baseball bat.

Epic also spends time talking about the adaptive AI, called the “director” (if you played Left 4 Dead, that will sound familiar). This keeps players on their toes, as the game will read and react to player forts and actions.

Fortnite is currently in alpha testing. You can sign up to participate on the official website.