I have used the blackbox debug bar and it looks like the code would need a bit of refresh to remove few minor coding errors.
Can you please install and run it :
This will show you that there are few PHP problems in the code. Not big issues, but the plugin would be cleaner if they were fixed. Some of these issues could result in random behaviours and hidden bugs...
Also, would be nice if the required files could be only loaded when there is actually a gallery showed. Right now, the CSS file is loaded on every page for instance.
Thanks a lot for your great job!