Do you think DD3 is harder than DD2?
I do, but I think it's for more reasons than just the removal of the Dragon Knee.
You no longer get "lives," but when a character's life bar runs out, they are just dead. Like, they tried to introduce RPG elements and stuff, like weapons having a set number of uses before they are used up, and whatnot... To me, it seems like it might have been better off as a new series entirely. Double Dragon didn't need a retool, it was okay the way it was.
Super Double Dragon, on the other hand, isn't as hard, but also feels kind of empty; as dumb as they are, I miss the story scenes from DD1-3. Super Double Dragon is just like "why are we beating all these people up? Who cares!!" ...I mean I get it, that it's not strictly necessary. But... I dunno, give me something to care about, so that when I beat it, it's not just like "Well, that's it." It has no ceremony to it.