Added an appdata file. It's incomplete though:

New screenshots are required, which must be in 16:9 aspect ratio for
appdata. The older screenshots aren't of the 0.6 version, and aren't of
the correct aspect ratio either.

Refer:
http://blogs.gnome.org/hughsie/2013/10/08/how-to-take-169-screenshots/
https://lists.fedoraproject.org/pipermail/devel/2013-September/188799.html

I can generate screenshots on my machine and send them to you if that'll help. Also, I haven't tweaked the install scripts to install the appdata file. It needs to go into /usr/share/appdata/ as the above links describe. 

I'm the Fedora maintainer for labyrinth. It's available in the repos now. If you can host the screenshots somewhere, i'll go ahead and immediately push an update so a complete entry can be shown in gnome-software.