Unix
You shoot yourself in the foot.

DOS
You keep running up against the one-bullet barrier.

MS-Windows
The gun blows up in your hand.

Windows NT
The gun is so huge and unwieldy that you have to keep swapping it from one hand to the other.

OS/2
The gun and the bullet aren't speaking to each other any more.

Mac Finder
It's easy to shoot yourself in the foot -- just point and shoot.

AIX
You can shoot yourself in the foot with either a .38 or a .45.

IRIX
The Terminator shoots you in the foot. A T-Rex bites your other foot.

SVR4
The gun isn't compatible with your foot.

Minix
You learn how to shoot yourself in the foot with a Saturday Night Special.

Linux
Generous programmers from around the world all join forces to help you shoot yourself in the foot for free.

HURD
You'll be able to shoot yourself in the foot Real Soon Now.

VM/CMS
IBM shoots you in the foot.

VMS
FOOT ambiguous: supply more toes.

AMIGA-DOS
The gun works pretty well, except that few people use one and it's impossible to find bullets.

Mach
The bullets work pretty well, but they don't make guns for it any more.

Cray
You shoot yourself in the foot with an Uzi.

MasPar
You shoot all of your friends' feet simultaneously.