> Any chance you can add the abilities to browse multiple folders and to work with aliases? I can’t see using this app regularly without the ability to grab a couple of folders and go.

Aliases maybe, multiple folders no.

> Other small requests… ability to set the keyboard options, especially I would like to be able to choose the buttons that move from image to image, or have ‘f’ toggle full-screen without requiring the command key.

Already there, in the Preferences.

> The 'Include Images from Folders' should be sticky. You shouldn’t have to check it every time (and only after the slideshow has begun).

It is, but it is remembered per-folder.

> This is a bit more difficult to explain but I’d like to have the ability to view a large image in two steps. Essentially, open the image so that it fits the top half of the image across the screen and then hitting a key will drop down to display the bottom half of the page. You can zoom in on an image now but tapping space will then move you to the top of the next image (which is still a useful ability). I’d like to advance the image in both ways. In a nutshell, this would mean cycling through all the images with two taps per image without missing anything. Being able to cap the zooming so that for example, a 100 px image wouldn’t fill the screen in this scenario would be good too.

This is also there. Use command-arrow.