REANIMAL is playable solo and in local + online co-op, with a shared, directed camera designed to increase claustrophobia and tension. The Steam feature list also includes Cross-Platform Multiplayer.
For co-op details, start here and follow the links below.
REANIMAL supports:
Source highlights: official site confirms solo + local & online co-op and the shared directed camera.
Both the full game and the demo list Cross-Platform Multiplayer as a feature on Steam.
Cross-play matchmaking rules (which platforms can invite which platforms) may vary by platform and region—this page will be updated when more official details are available.
Tarsier states that you can let a friend play for free using Friend’s Pass. Details (how the invite works, whether the friend needs a separate download, availability timing) may depend on platform.
The camera is shared and directed—expect co-op to reward staying close, moving as a unit, and communicating.