I'm entirely aware that you can start it minimized with a parameter, but this creates a complication in using the manictime usb version with the PortableApps.com launcher as it only retrieves .exe files from the directory of apps to populate its list, not shortcuts or batch files (which if I understand correctly is where you could put the startup parameter)
I can't recall if the normal installed version of manictime starts minimized but it might benefit from this as well.