Kicking off the annual San Diego Comic-con, Epic Games has lifted the veil off of their co-op-focused sandbox game Fortnite -- revealing that the game is in development for PC for a 2013 launch, and will be the first title built on their new Unreal Engine 4 technology.

Unfortunately there are no new trailers to share yet (only the teaser from last December), but the first set of screenshots still look rather tasty.

In Fortnite, players will explore, forage, collaborate and build by day in their own dynamic and expanding world. At night, they’ll work together to defend their prized fortress from the forces of darkness.

Attendees also received a first look at Fortnite’s building system, which is designed so that players can use scavenged materials to quickly build and renovate structures of varying materials and complexity.

The Verge were present for the comic-con presentation, where Epic's Cliff Blezinski reportedly explained that the game originally followed a more traditional post-apocalyptic aesthetic inspired by The-Road, but that the team found it too "depressing".

According to The Verge, gameplay shown demonstrated "a deep level of structure building that lets players build and edit each wall with a 3x3 grid, lay down stairs, roofs, and windows, sculpting them to suit a particular need".

Epic has since clarified that they have not ruled out the possibility of other platform releases in the future, but that the game will indeed land on the PC first.