Thankyou for taking the time to take the screenshot as it has confirmed my suspicion.
An updated version is now available for download which solves both this and the mouse issues.
Upon downloading the new version and loading your save (saves from previous versions will be auto detected), a blue warp will appear near the right wall. it will take you back to the entrance.
Overall congratulations on discovering this sequence skip, and I truly give my apologies for the experience being ruined as a result of my oversight.