Inside PlayerUnknown Productions' two-day modjam where devs broke their game

About an hour before presentations, Alexander Helliwell was reshaping Prologue's temperate woodland into a scorching desert. Replacing much of the world with sand even gave a performance uplift, but his map soon showed wide stretches of an unidentifiable black substance.

"Is that oil?" someone asked. Helliwell shook his head: "I don't know." In the last few days of 2025, PlayerUnknown Productions gathered developers in Amsterdam for a two-day modjam. Staff travelled from across Europe to Mokum not for stand-ups but to see what happens when a team is let loose on its own game, using a rough assemblage of UE5 asset-store props, the game's pre-existing systems and whatever they could build in 48 hours.

Teams spun up new mechanics, items, systems and total conversions, even producing mock Steam pages and ads; standout ideas might be folded back into the game.

playerunknown productions, modjam, game jam, ue5, unreal engine, prologue, amsterdam, mokum, modding, steam pages