Now that Flappy Bird has been removed from the Google Play Market, people who missed out will need to manually sideload the game directly to the device. The process is simple and will take less than 2 minutes.
Install Flappy Bird to your Android
1. Go to Settings
2. Press “Security”
3. Enable “Unknown sources”
4. Confirm the warning
5. Go here to download the Flappy Bird .APK installation file: http://www.mediafire.com/download/1r897c4vwqe61g3/Flappy_Bird_1.3.apk
6. After the file is done downloading, open and install the file