The overlay does not work for me when I have riva turner on.

When I remove riva turner it works but only chat options appear. This does not let me see achievements or statistics

Ah yeah, sadly I always have to close MSI Afterburner before using Galaxy, if I want the overlay.

The overlay doesn't show achievements, that's just how it is.

Seriously ??? and do not think to correct these errors ???

I don't think it's an error, it's just not functionality that exists yet. Perhaps put in a feature request for it on the issue tracker if there isn't one already?

It will show when an achievement unlocks but no you can't see a general overview of all your achievements as of the current version.