I made an Infinite Runner 2D game with Unity last Monday and I pushed it to my github. You can have the entire source code here. If you prefer to copy the link, it’s here: https://github.com/joaokucera/unity-infinite-runner-2d.
You can also play a webgl demo here.
There is no license, no condition, download and use it as you wish. I hope this helps you to study #unity3d and if this help you then give me a github’s star.