I have been in to game programming for some time now, and recently ventured out in to trying to create my own pixel art. So I have learned the basics of lighting and shading etc. and noticed that several games will light their tiles from the top left. Such as Super Metroid and Axiom Verge highlighted in red here:
I assume because there is no distinct light source, one was chosen and consistently applied everywhere where possible?
Why does it tend to be the top left, is it to do with westerners reading left to right, top to bottom perhaps?
And bonus question, what is the reason behind the opposite side shading shown in the blue circle in Axiom Verge?