Retro Bowl is a popular mobile game developed by New Star Games. It has tons of cool features like playing full seasons and managing your teams pretty much just like the old school Nintendo football games of your youth. However, if you are here I am guessing you want to learn How To Throw A Bullet Pass In Retro Bowl. This one is pretty simple.
1. Use your finger to pull back just like you are throwing a normal pass:
2. Tap with a second finger to convert to a bullet pass:
3. Enjoy!
The bullet pass can be great for make hard throws on curl routes. However, I find that the receivers drop these a lot more than just the regular pass so YMMV.