Rated 4 out of 5 stars
I have MacOS 10.4.11
I had to add "Extensions.checkCompatibility::false" to about:config, but now that I installed it, it seems to work.
It make the game use the full browser window although it always says "no flash detected"
I use with the FaceBook games (like http://apps.facebook.com/lilfarmlife)
Please read the "important note"
Please refer to the "important note to all users" on the main page, for an explanation of (and two ways to fix) the "no flash detected" issue (you can either download version 1.3.6 or start using the toolbar-button to make the button(s) work as intended).
With regard to the compatibility issue: Unfortunately I was given the impression that FGM 1.3.0 didn't work on Darvin (Mac OS-X) platforms, prior to uploading it. Accordingly I set the compatibility to "Windows" only. If you want to avoid the checkCompatability::false hack, try installing version 1.3.6 (available on the "Old Versions page", even if it is in fact a newer version), which should have its compatibility set to "ALL".