I really wish there were more YTPMVs with this tune.
Disclaimer: don't listen to this for too long.

Sources:
"Gravity" by drperson12 https://www.youtube.com/watch?v=d5jp7c0n5PM
"Jun-chan Gravity" by yamas03 https://www.youtube.com/watch?v=5JHmNUcf-N4

BGM: https://www.youtube.com/watch?v=MmKOOsxSiOA