Review and Ratings:
Concept/Innovative : 0.6 - This seems like a reskin of one of the famous app with little variations. Difficulty level is much higher and therefore makes it more challenging.
Usability: 0.9 - Easy to understand
Functionality/Correctness : 0.9 - No major issues found.
User Interface : 0.5 - User interface is average.
Performance : 0.6 - It works great but it does lag sometimes while accessing achievements or leaderboards !