The Scrolling Parallax Levelling Game - RJM Programming - August, 2019 ... thanks to W3schools and Cody

Scroll Up and Down to take a (optionally offsetted ) with your level.
BacksightInter SightForesightHeight of
Collimation
Reduced LevelRemarks
OBM
BacksightInter SightForesightHeight of
Collimation
Reduced LevelRemarks
OBM