Tap Tap Revenge the second-most downloaded free application of the year from their App Store, and the most downloaded free game. In April 2009, internet marketing research company comScore announced the results of a study which claimed 1 in 3 U.S. iPhone OS users had downloaded the game, and that it was the most popular application for the iPhone and iPod Touch. As part of the 2nd generation iPod touch advertising campaign, Apple featured "Tap Tap Revenge" in print and television ads with the headline "The funnest iPod ever.". The game spawned three direct sequels, "Tap Tap Revenge 2", "Tap Tap Revenge 3",
IPod Touch to the iPod Touch as "training wheels for the iPhone". All iPods lack Touch ID, 3D Touch, NFC, GPS, an earpiece speaker and a noise-cancelling microphone. Depending on the generation, the iPod Touch may have a smaller or inferior display and camera(s). Newer models (5th and 6th generation) lack the ambient light sensor that makes automatic brightness available. Older models lack a built in speaker, a microphone, a camera, and a flash. No iPod Touch has a modem through which it can place phone calls or send SMS and MMS. However, 5th and 6th generation models can either piggy-back on