Thank you!

This is really great work by the way, I really like some of them, Yamato Man redo is my favorite.

Since you asked for C & C , I like to point something up.

First, the robot master with question mark, I believe the *green shade is culprit(0 64 88). When using as shading, *green are not really good against red/orange(or any strong warm color). But you can broke that rules when working with super limited palette(only green and red allowed), or against desaturated red/orange. Since this is limited NES palette(doesn't have desaturate color), the best bet is to stick with dark brown(80 48 0) as your darkest warm shading.

Second thing I would like to point up, is that some of the portrait are overly shade, especially their eyes. So, the portrait had lost some of the important focal point, and that is what made Rockman such an iconic game I believe, the "intimidating stare" from each robot master. You did a great job on Aqua Man, nice contrast on his eyes.

I'm not a pro my self, so feel free to correct me if some of my opinion are wrong.

*Edit: Actually it's green+blue(still in cool color category), but the same rules still apply.

Beautiful palette 

This is so funny hahaha

That electric effect are really cool!

Thank you so much!

Thank you for the feedback! To be honest, I tried to put some background effect(like horizontal line, explosion line), but the outcome seems like doesn't look good, so I just settle with plain pink. Do you have any suggestion what should I do? I am still new with pixel art, there is alot to learn 

Thank you!