Johnson is actually a character as well as the weapon Garcia uses throughout the game. Johnson is a former demon who can transform into many things including a torch, pistol (called the boner), machine gun or shotgun.
Shadows of the Damned is full of adolescent jokes that leave no doubt in the player's mind what the maker's are playing at.
One of the upgrades to to the boner or the handgun is to the hot boner, which allows you to break cracked objects by blowing them up or if stuck into demons it also explodes. At one point in the game Johnson even tells Garcia to "fill those crack with your explosive Hot Boner."
The references are clever or subtle making the comedy rely on whether or not you get a kick out of blunt humor.
There are some videos circulating already that are highlighting this aspect of the game. One is sort of a spoof infomercial for male-enhancement while theother is simply a montage of "johnson" references in the game.
Is it just enough to be funny and lighten up the City of the Damned? Or is it too much? Tell us what you think in the comment section.