This could be your greatest fresco yet, Orioto!
My suggestions for improvements (I hope I'm not too late...):
1. Robot master order is
important part of the Mega Man games and I would love to use this artwork as a walkthrough guide each time I replay the first Mega Man game.
Suggested order:
http://www.mmhp.net/GameHints/MM1.html#Order
You should number the boss fights like I have done in the picture.
P.S. It doesn't matter at all that the stage/level panels and Mega Man suit/power combinations don't follow this order.
2. Bomb Man stage: I moved the big blue power up from the Cut Man stage here (made it a bit bigger and darker blue). I added a firing Mambu.
3. Cut Man stage: I removed the big blue power up (Mega Man should have picked it up on his way to the platform). I added the second Adhering Suzy and a firing Mambu (altered the green bricks a bit).
4. Fire Man stage: I added a small white power up and a 1up Mega Man head (altered the platform under it). 1up Mega Man head is a must!
5. Ice Man stage: Center of the panel looked too empty so I added one Pepe (penquin). Pepes should have white speed/movement trails! I also added a big white power up (under the water so lightly blue) and a Foot Holder.
6. Mega Man should have the Guts Man / Super Arm suit in the Yellow Devil panel (Mega Man isn't shooting so it is a perfect fit).
7. Doctor Wily should be visible in the final battle panel (but I'm sure that was already your plan...).
8. The final picture should have FIN or THE END text. I would prefer FIN since you are a French artist.
I will definitely get at least one large fresco, if you add some of these ideas to your work. Those numbers are very important to me. And those enemies. And power ups. Small details and fixes. Ahh... I want it all!!!