The new update gives you the opportunity to post scores for each level plus the overall score for all the levels. You will need to update from the apps store to be able to post individual levels.
Zero Gravity lite has just been added to the apps store. The lite version only has 8 levels. You can still post scores on game center so download and have a go. Click here to view in the apps store
Zero Gravity was launched on the app store on June the 5th 2012. Currently with a 5 star rating.