Really? 6 reviews is considered a lot for an indie game already. If you're expecting your game to have as many reviews as the likes of Pom Gets Wifi or Dreaming Mary, then I think your expectations are way too high. You should be glad that your game even got a review. It shows that people care.
Well, actually, if you really want more reviews, Steam would be the way to go. Only that reviews in Steam are generally not as substantial as the reviews here at RMN. And Steam are generally for commercial games. Just saying.
I think rather than just expecting reviews, you should also look at comments that give opinions as well. You can also consider setting up a Google Form of sort asking people to give feedback. You'll probably get more feedback that way (because with Google Forms, people can give feedback anonymously without having to register for any account).