Crossplay

Is SteamWorld Heist: The Outsider crossplay?

Crossplay does not apply to SteamWorld Heist: The Outsider: it has no online multiplayer.

"SteamWorld Heist: The Outsider is the game’s first DLC pack. Captain Piper stumbles upon a new ally with a past shrouded in mystery. Dive into the action with new playable character and take on new missions with brand-new weapons, gear and a shipload of hats! All new content blends seamlessly into the game. Aside from starting afresh, you can pick up earlier save files and discover who the outsider is pretty much immediately…"