...How is Act 3 still not public? Unless it's exclusive to downloading the game from the site or something akin to that...
It's just a matter of content and polish. Act 3 still has nowhere near the amount of endings or TFs as any of the other 2 Acts, and still mostly relies on the Quickstart Menu to actually jump into it. It's still very much a WIP and has almost my full attention for the foreseeable future.
Access to Act 3 and any other 'non-public' content will always be available for any tier on the Patreon.