Detached is always going to be free to play.
However, Early Access is always going to be a version ahead of the free release, meaning there is going to be a 1-3 month window where the most current version is only going to be available here or on Patreon/SubStar.
When development for Detached is officially complete, there will be a generous Early Access timeframe where the final update is only available for Early Access before I release it publicly.