The multiple Busters on screen together were created in the camera, using a special lens with shutters to film only a portion of the scene at a time. Buster would perform one part, then the cameraman would crank the film back and open another shutter to film another part. A banjo player with a metronome helped Buster Keaton to perform precisely at the right time for each take.
Buster Keaton used a hand double in the shot where he writes, to avoid showing his right hand with the missing index fingertip.
Buster Keaton's stunts are tame in this movie, compared to his usual rugged and demanding stunt work, because he was recovering from a broken ankle.
In this short Buster Keaton took credit for every part and job, including editor, director, writer, cameraman etc. This was an allusion to Thomas H. Ince's (the "inventor" of the Western) reputation for doing this.
The film was restored in 2015 through Lobster Films, a process partially funded through a Kickstarter crowdfunding campaign.