now i know how to use them, and i know you can do like collisions and stuff between different groups etc, but i want to know, what all can qualifiers be used for? is there more to it than just grouping objects? and also, can backdrops use qualifiers too?
[Game design makes my brain feel like its gonna explode.]
Only actives can be qualifiers. Just treat a whole qualifier group like you would an active. Say you could have some enemies that you only want to appear if the player choses a hard difficulty;
start of frame+difficulty is low= destroy qualifier.
The only problem would be from MMF2s object picking. Sometimes you just want one object in a qualifier to do something. Sketchy did a great article on it here - http://create-games.com/article.asp?id=1975
And just so you know you can't add qualifiers to the global events page. God knows why but its there.