pc engine duo DD2 was a much faster and improved significantly on the nes, nes only had 2 enemies on screen due to technical limitations, pc engine duo had more, combined the fact that pc engine duo version was much faster, thus, the pacing and action seems more frantic
in fact, even if you compare to the super dd, the pc engine duo seems more exciting and better variety, but the snes /sfc was visually and technically better ( I recall up to 4 enemies on screen), on the distant cousin, combatribes on snes/sfc kills pc engine duo dd2
while the Gameboy advance, which is from a different era is one of the best versions, unless you consider the improved android arcade port of dd2 ( which I love using dual shock 3 ps3 joypad on my xperia z2 and z tablet) which was released a few years ago