Secret Dr. Right Capsule - Hadoken!
Yes, it's true. The Fireball attack from Capcom's Street Fighter game
series exist in this game. To get it, you need the following items: All
8 Weapons, 8 Life Ups, 4 Sub Tanks and all 4 X Capsule
Parts. Enter Armor Armarge's stage and rush through it 5 times. At the end
of each rushthrough, you need to land on the empty spot above the Maverick
room door of the stage, Exit the stage and reenter it, repeat this 4 more
times. On the fifth run, the capsule containing the Fireball will suddenly
show up out of nowhere.
You don't necessarily have to rush through the stage 5 times completely.
After landing on that empty spot above the Maverick room door, you can kill
yourself by jumping down the pit and start from the Check Point of that
stage and it will still count as a rushthrough.
To perform the Hadoken fireball,
make sure you have full Life Energy, then input this command quickly on
your controller: D, DF, F+Fire (It's the opposite direction if you're facing
left). The Fireball (upon impact) will kill ANY enemy and boss in the game
in 1 hit. It won't work against Sigma's 2nd Form though.