I had a lot of fun customizing it, the best part of GNOME Flashback? Well, it doesn’t mess my main Ubuntu desktop environment, in fact, both DE look very similar and have the same icons!! Only “Main Menu” was installed but it only affects GNOME Flashback. I love GNOME and Ubuntu so much.
I didn’t realise this option existed - and it’s an interesting one, perhaps giving the ease-of-use of Mate/Cinnamon/Gnome 2, without sticking with the older code.
Flashback is based on old GNOME 2 code but unlike MATE it’s not maintained or improved.