At Penny Arcade Expo in Seattle last weekend, Valve showed this trailer for the first-person puzzle game’s co-op campaign behind closed doors. Now you can see it for yourself. Aren’t you lucky.

Instead of a human test subject, Portal 2 ‘s protagonists are a pair of adorable robots. Don’t worry if one of them is flung into a wall, or falls off a cliff, or is otherwise burned, crushed or mutilated by Aperture Science’s many devious testing facilities. They’ll come back to life.

Watching this trailer does give you a glimpse of just how complicated playing Portal with two players — and two independently-controlled sets of portals that ruin everything you know about Euclidean geometry — will be. Make sure to pick a partner who won’t stab you.