Easy Final Fortress Stages:
After you have defeated the 8 Robot Masters the Final Fortress stages will become unlocked and you will fight Dr. Wily. The Final Fortress bosses each have the following unique weakness you can take advantage of.
Wily's Fortress Stage 1:
Use the Buster against the eye.
Wily's Fortress Stage 2:
Use Fuse on the exterior, and Impact in the center.
Wily Boss Battle Stage 1:
Use fully-charged Blast.
Wily Boss Battle Stage 2:
Use Fuse from below.
Easy Robot Master Fights:
You can easily defeat all the Robot Masters by fighting the bosses in the following order. Ater defeating a boss collect their weapons and use those weapons on the next Robot Master on the list.
Unlock Extra Bolts and E-Tanks:
This can only be done once. Download and play the demo version of Mega Man 11. When you then download the full version you will be able to start a new game with 300 bolts and 3 E-Tanks.