Most times when I go to revisit a 16-bit game from my childhood or play a new one, I don't enjoy them as an adult. In a lot of cases it's the insane difficulty or the unfair challenges, but often just the nature of them being mechanical to the point of breaking immersion.

Sunset Riders is one of the few games of that era that I feel has an appealing aesthetic, well-structured progression, and a high skill ceiling, while also being accessible to casual players. I've beaten this game several times, and each time it's a blast from start to finish. You shoot everyone in sight while dodging bullets by sliding, jumping, switching between two elevation levels, or entering saloons for some hot hooker action (the sex is not shown but heavily implied). The gameplay is dead simple, yet every minute of it is meticulously designed to make you feel like the protagonist of a John Woo movie or Neo from The Matrix. And it never grows stale either because levels are rather short, and each has its own quirks while also standing out aesthetically and featuring regular scripted scenes.

I've never played the Arcade version, which everyone says is superior, but I did play a bit of the SNES version once, which is supposedly closer to the original. I still have to play through it to make up my mind completely, but based on what I've seen so far I will say that I prefer the Genesis version. Firstly because of the colors: the skies are "Sega-blue", and the landscapes have a more natural palette. Secondly because IIRC the two extra characters in the SNES version play the same as the two they kept in this version.