The only problem with the Babel fish puzzle (as I remember it) was that if you went through, being clued by the previous press of the vending machine button, th

The only problem with the Babel fish puzzle (as I remember it) was that if you went through, being clued by the previous press of the vending machine button, the machine would run out of babel fish before you got one. So...go back to a save. But then realize you didn't have the junk mail, so start the game over from the beginning. Modern IF games usually make it harder to get your game into an unwinnable state.