Default [GAME][2.3+] Addition - Simple but Challenging

I created this game so that I can learn about Play Game Services. When I published it, some of my friends liked it and got a lot of feed back. It took me about a week before I can actually beat the game that I made. I decided to share it in this forum, maybe some of you guys will like it. Please feel free to rate and comment. Thanks!

An addictive game that tests your concentration, patience and logic. Select the correct answer before the timer runs out. You beat the game by getting 15 correct answers. Sign in to google to determine your ranking with the rest of the world!
Game Features:
  • Achievements
  • Leaderboards
  • Score sharing