Hi,
Them & Us is going to be available as an Early Access release on September 8, 2018, you can now send your feedback and work with us to achieve a polished and immersive game experience.
"Early Access current game build status"
https://steamcommunity.com/games/915600/announcements/detail/2693605177438008523
"Partial controller support?"
Unfortunately we cannot set the game as a full controller support since for "one time only" an Epic Games EULA message appears on launch that can only be bypass by mouse and keyboard. The game works perfectly 100% with a controller from start to exit.
Best Regards,
TendoGames