In the .gcf files, there is a scrapped weapon mechanic which was intended for the K.B.G. With it, every kill would earn the Heavy, and his surrounding allies, 50 health regenerated and an additional 10% to their critical hit chances. The downside was that the Heavy taunted after each and every successful K.G.B. kill.
In SMB, mario was suppossed to have a gun in 1 stage.