My two challenges with the medium format Diana F+ camera from Lomography are holding the camera steady, for the slow shutter speed, and selecting the right focus range prior to shooting.
It may be more than that. Without thinking, yesterday, I shot a few pics with the cloudy aperture in sunlight. No doubt they will be overexposed. They may be completely blown out, or be ghostly white. Once, I even forgot to remove the lens cap, which isn't so bad given the manual film advance.
My current roll has the frame mask for 16 rather than 12 photos. I am curious how they will turn out. Shooting with the toy camera is simultaneously simple and difficult. The simplicity is what makes it so difficult.