Double Dragon Neon
because it's the only good game in the series.
for real, I don't quite get why people like or ever liked Double Dragon, must be due to the lack of alternatives in the genre.
the fighting system in all of them is trash, the controls are stiff, the enemies often annoying to fight... they are just not good.
Neon at least brought some amount of depth and interesting elements to the mix, but it also didn't play that well tbh.
so basically, I vote for Neon because it's the only actually good game in the series, even if it's still worse than even old 16bit arcade titles of the early 90s