I'm kinda mixed on the game so far. On one hand I can see and feel some of the visual improvements over the NES titles. On the other, while I like how the game's tone is more Mega Man 1 and 2, the sprite and tile work really is bland looking even compared to the first two games. The music is catchy though, I'm glad that they didn't fuck that part up.
Also I'm all for hard difficulties and such but some of the challenges in the game rely on stretching out a mechanic for far too long (Tornado Man) or one hit deaths. It's more tedious than challenging. Some of it just borderlines a typiclal Mega Man hack without being nearly as difficult. There's also some enemy placements in the game that I can't seem to get by without getting hit, like one involving a ladder and one of those spider hoppers. Also what's with Machine Gun Sniper Joe not having any sound effects?
Despite my problems with it I am enjoying the game a lot so far and there are some pretty creative twists here and there, but the level design does feel a bit chintzy than what it should be for a newly released 8 bit game.
As for my series rankings:
1=2=3=7nes > 5 > 6 = 4