What are the two fonts that say "GREEN HILL" and "ZONE". I guessing that they were originally more detailed and were pixelised for the sake of the game it came from.

Righteous  Suggested by Xonix The Hedgehog 

The font you are trying to find doesn't have to be pixelised like the one shown. It just has to look like this when viewing in a lower resolution.

Maybe it doesn't recognized yet because the characters are pixelated, and not computer font.

So people here use a program to detect what font it is? or do they know by recognition, knowledge and memory. Maybe I'm asking for a custom font specifically made for Sonic Mania.

I Found It! Its a Closest Font Is Righteous! The Letters A Different Letters Are "G","R","N","C","P" & "S". And Its Free!