The Gepe slide mounts with glass don't squish the film flat like a glass negative carrier. Although the literature does not say, I suspect the Leica lenses are curved field to account for that. Was the projector perpendicular to the wall? I the projector was aimed up to the wall, it won't all be in focus unless you use the PC-ELMARIT-PRO (perspective correction) projector lens. Otherwise prop the projector up in height so it is level with the middle of the screen and see if the focus is better.