All the Yen-type cameras operated on the same premise, using film that did not require darkroom loading or processing. (Camera literature often referred to this as "No need dark room" film). 

Each piece of cut film was attached to a strip of paper, then placed in a lightweight  paper holder (shown in second photo at right) and inserted into the back for exposure. Following exposure, the film was dipped into a red developer, then a green fixer to complete the development process.

Other variations have been referenced which have carrying straps, reflex finders, even different lens/shutter combinations. But at its heart this was essentially a novelty camera not intended to last a lifetime.