Tap Tap Revenge 4

Tap Tap Revenge 4 is an app for the iPhone, iPod touch, and iPad developed by Tapulous, Inc.

Gameplay
In Tap Tap Revenge 4 round shapes (which are meant to resemble notes) slide down a certain colored row. When the note gets into the circular area towards the bottom of your device, you need to press it. Some notes are just one press, while some you have to hold.

Usage of Game Center
Tap Tap Revenge 4 uses Game Center for a leaderboard.