Flashback is an unlockable achievement for the Bloons TD game for the iPhone and iPod Touch. All Achievements are provided by an app called OpenFeint. You must have OpenFeint installed in order for any achievements to be available.
This achievement is unlocked when you complete the Classic 2 pack on Easy Difficulty or higher. It awards 10 points upon unlock. It is the bronze achievement for the Classic 2 pack, as indicated on the achievement's picture.
- Silver achievement - awarded for completing the pack on medium or higher.
- Gold achievement - awarded for completing the pack on hard.
As indicated by the achievement names, if you complete the pack on Hard Difficulty, you will unlock this pack's bronze, silver, and gold achievements (if they have not been unlocked before). The same goes for completing the pack on Medium Difficulty; you will unlock the bronze and silver achievements.