Great just installed the latest version from the OP and have now removed "flashlight".

If you really feel the need for a cut down version of Lanterne you could call it Torchio I don't think I need it now.

If you feel it's useful you could add an option to lock the screen too on lens close/application close, however I use a separate application to do this.
It should be simple to add in, you can call the command via DBus.

The only final comment I have is your preferences windows (all pasta shapes) seems to be a few pixels too big for portrait operation.
If scrolling was only available vertically and the window and contains was slightly smaller. The preferences window would work really well.

I like pasta, hopefully we will see many more varieties.
I am sure there are many more simple but much needed applications.