A full Unity3D Example project, published on the Google Play Store at https://play.google.com/store/apps/details?id=com.gmg.bullet.
This project was fully developed on stream at https://www.twitch.tv/realgmg
The code overview is also available on Youtube at https://www.youtube.com/channel/UCr_hDk1LLtuhkzt0goR95Rw?view_as=subscriber
I am currently developing other games on stream, so make sure to stop by if you're interested!
As for license, feel free to use/modify this code however you like. A heads up / shoutout is always welcome of course! Beware that the song used is free to use but requires you to credit the creator.
Hope you have fun!