Love the achievements, and would love to put forth some suggestions to add to an already promising plugin.
Firstly is displaying the Featured Image for an achievement in the user achievements tab for ourselves and others:
Also displaying the Featured Image for an achievement in the shortcode for displaying the index:
In the footer I am displaying the Photo Grid, but as it is showing "Available Achievements", can it hide the ones I have already achieved? And show them all for the logged out user?
Can a message be displayed on each achievement on my status of that achievement (green bar "Achievement Unlocked" or red bar "Achievement not yet Unlocked")?
Some other suggestions:
Can the Karma award be shown automatically in the post?
Can the steps be shown automatically in the post?
Can we have timed achievements?
Can the modules we don't have installed be hidden from the required steps area?
I have a bunch more, but I'll stop now as to not overload the post :P