Sorry about that! We probably should have made it clearer in-game but right now only the first act and a few scenes of the second act are available. Once the full second act is released, your save file should just continue from that point on instead of returning to the title.
If you want to know more about the development progress, we explain it a bit more in our devlogs.
We're happy you enjoyed the game so far and we hope waiting for the next acts won't be too much of a problem! Thanks for playing <3