150 possitive reviews in 15 days and game is still not climbingin the charts

hi i would like the help of the community to let me know what are we doing wrong.

We are a small Indie (3 People) and we released our FREE game for IOS called Atlantis Breaker HD, you probably didn't hear of the game unless you are in the cocos2d community...

The game is FREE and it went live on the 15th of February 2013, till today we got more than 150 reviews with an average of 4.3 and we still dont see us in the rankings..

Any help, advice, feedback will be welcomed. Game name is Atlantis Breaker HD link is : https://itunes.apple.com/app/atlantis-breaker-hd/id576385319?mt=8

thanks, Meital

150 possitive reviews in 15 days and game is still not climbingin the charts
itunes.apple.com