Looking up images of DOS platformers like Secret Agent and Crystal Caves reminds me of a game that was loaded on some elementary school computers in 1998. I don't recall if they were Mac or DOS, but they certainly weren't the cutting edge G3. I think the game had a character in a trench coat and they were maybe a sleuth of some kind. The color palette was dark but there were yellow-ish lights coming from above in a conical shape.

I know memories are usually warped and wrong, but hopefully this is enough of a description to jog someone's memory. I have been able to rediscover all of the games I played as kid. Most I never revisited, but it feels satisfying to learn what they were. Big ones that bugged me for ages are Tyrian and Descent.