Bokujou Monogatari GB (Rev A) is a revision of the original Japanese Game Boy release. The 'Rev A' designation suggests improvements and possible bug fixes, perhaps graphical or performance-based.  Its gameplay maintains the core farming simulation mechanics of the series.  The details on the specific changes from the original version and developer is unknown without additional research.

Bokujou Monogatari GB (Japan) (Rev A)

Bo Jackson 2 Games in 1 - Hit and Run! (USA)