It seems like everyone is suggesting hiding old ver. of your game and uploading a new ver. As the creator of Bio-Gun I wanted to point out that I kept updating the same game ver. insteading uploading a whole new game and hiding the old. You wont believe how many times people will come back to your game to see how your game is doing and if it has been updated. My advise it to be as responsive as you can in your comment section and to make sure to upload a new ver. at least once or twice a week.
As to your original question.
Make sure when you post your games on any forum including scirra arcade you have a very solid first build. 90% bug free, polished, and attention to small details. People who play your game will feel respected and will come back to it more often.
-Best of luck to you and your future endeavors tallenwebdev!