Zynk, I've left you reviews of Roll-Chan 2, 3, and 4. Really love your work!
And actually, I'd like to help with Roll-Chan 5. I don't have rom hacking experience parse, but I am something of a sprite artist and am very familiar with the Famicom Rockman games.
In the case of Rockman 5, seven of the eight robot masters are improperly colored in game compared to their official artwork counterparts, the worst being Crystalman and Naplamman. Their primary colors are just simply wrong in-game. I am aware of the three colors per sprite limitations of NES graphics as well as the NTSC color pallet. Taking those into account and specifically how the Megaman bosses are constructed using three sprite layers, here's an example of my work with Crystalman:
This shows two possible coloring solutions that work to make Crystalman more dynamic looking in game. I have colored all sprites to show what he would look like in each pallet.
The first uses a darker pallet imitates the green of the original sprite, while still retaining some blue traits.
The second uses exclusively light blues and closely matches the original, official artwork of the character. I feel this is the better choice, and no offense, superior to the concept of a light blue Crystalman posted earlier.
What I am not sure about is the proper names for color pallet addresses, so included in my image is the NES color pallet. I've listed the new color changes according to an X-Y grid format. For example, the dark greenish blue primary color of the first Crystalman is listed as C-1. That means it is C in the horizontal column and 1 in the vertical column.
I'm working on fixing the others as well, but Crystalman is the most extreme example.