Actually Bounce rate is the factor that indicates the ratio between number of visitors viewing only one page of your site and the number of entries to our site. If you get high bounce rate means viewers are closing your site without viewing more pages and spending less time in your site. I saw your site and it looks nice. I have a question for you
1. Did you submit your website's link on other unwanted, irrelevant websites? if you did so then your bounce rate will surely increase and also your website ranking will decrease. If you have low quality or irrelevant apps in your site, your websites bounce rate will increase.
Methods to reduce bounce rate:
1.In order to decrease your bounce rate, check all backlinks of your website. Use back link checker tool and filter and remove irrelevant and unwanted backlinks that targets your website.
2.Go to webmaster tool and Click Traffic and again click 'links to your site' option. You will find all your internal backlinks. Remove all the unwanted backlinks if you have authority otherwise just Disavow all those thinks using Google disavow tool ( https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&sqi=2&ved=0CCwQFjAA&url=https%3A%2F%2Fwww.google.com%2Fwebmasters%2Ftools%2Fdisavow-links-main%3Fpli%3D1&ei=UXqtUbT_M4-IrAf3uYGIBg&usg=AFQjCNHQtgJnBhcFrPSIcWWzisTQNsRd3w&sig2=UAN3Nmm2EGh-kYtekA-tUg&bvm=bv.47244034,d.bmk )
3.Don't Open and close your webpage frequently without viewing more pages because while calculating bounce rate Google would calculate your own page views ( Direct Visit ) also.
3.Provide user friendly and user likeable content and games in your website
If you do all those thinks your website's bounce rate will surely decrease.
All the best