I keep going back and forth with my thoughts on this game. On one hand it has a basic foundation of it being a throwback to the NES era. Each level has a unique theme and music to go along with it to represent the game series is it from. Plus the 3 playable characters have unique skills like Beck's Dash attack or the fact that Gunvolt can double jump. Along with all of that every boss has a different pattern you must puzzle out to achieve victory.
Which is all countered by that fact that this game is just so short. Every level is really simple with very few variations that only appear in the extra set of DLC levels put into the PC release. I've played the 3DS version so my time is most likely shorter than most but a game being beatable in less than a hour is really short for a game these days. This game could completely work within these limits yet the fact that it rarely challenges the player to get better at playing the game is its downfall.
I genuinely like this game but it is such a hard game to recommend to anyone. For most players I would expect they would just play through it once without playing any of the other characters. Thus I can't say that this game is worth playing.