Im on a new one and ill try again
The web (public) version, as you can see from the sidebar, is prior to the one where the scene was added. Therefore, the scene is only present in the downloaded files that are at least v 0.81.0, and are only accessible to backers.
P.S.
It mean you must unzip the zip file and double click the html file or, if you are on an Android phone, install the apk file. This way, you can play the latest version.