Hello. Would be nice if we add information and a reason why Peek won't start on non-GNOME DE and when ffmpeg is not installed. For example Fedora users complain that app is broken and not working if they run under Cinnamon DE, see this issue. Easiest way to fix this is adding gnome-shell as hard dependency, but in same time this will annoy non-GNOME users even more since they forced to install many packages and whole GNOME session.

Since silver bullet doesn't exist, would be nice to show some kind of error or information dialog saying why it wouldn't work in the places it wouldn't work and suggesting users install whatever to make it work.