River City Ransom was a beat-'em-up for the NES that was released in 1989 but still has a pretty respectable online following. To judge by the fanpages, this is in no small part because it has enemies who say "BARF!" when you defeat them.

But why would they say something so bizarre? Because the original Japanese was:

"げーっ！", or gee!*. This is not really a word as such. It's a representation in kana of a more primal sound, something that comes from the throat or deeper and might be rendered in an English comic book as "ack!" or "urk!", say. The sound of someone coughing or choking or... barfing. It's also a sound people voluntarily reproduce to suggest such a reaction, like English: "Ew!", "Gross!", "Oh, man!" In the absence of contextual information (which is how many game translations were done those days) "BARF!" is a perfectly reasonable attempt at Englishing it.

In any case, it would be churlish to complain, since that "BARF!" has brought so much joy to so many people. A "better" translation like "urk!" would actually have had a negative effect on the overall game experience. So barf on, residents of River City... barf on.

Lesson: Some of the hardest dialogue to translate from Japanese to English refers to the simplest, most fundamental human behavior: laughing, weeping, getting punched in the stomach by a guy in a white zoot suit.

* Hard "g", and "ee" represents a double-length version of the "e" in "get". Romanization fails completely here. And I haven't even touched on the little っ.