I am trying to complete the challenge where you can't use special weapons for four stages...I completed all 8 bosses with only the Mega Buster, and still did not accomplish this. Does it mean you can't die or continue? Does this have to be on the Dr. Wily Castle stages? Are you not allowed to use energy tanks? I don't get it...

It's not only the bosses, it's the whole stage. From the moment you start the stage the the moment you beat the boss, you're not allowed to change weapons.

Also, the Dr. Wily stages are impossible to complete without special weapons.

Dude, I didn't even HIGHLIGHT a weapon during the first 8 boss stages...

It may not register until after you beat Wily

hmm...i dunno if I continued that file after beating all 8 stages....