I was watching this short video on little-known things about the original Metal Gear Solid, and you hear one of the lines that he changed--and a ton of players, myself included, probably never heard this particular line until now.
The "onion" line was not in the Japanese--and by extension, is not in the Twin Snakes version. One of the top comments on that video talks about additions like this being why he was fired. The story seems to track, as far as I can tell.
Later games stuck much more closely to the script. Maybe a little TOO closely, like MGS3's Volgin mumbling "Kuwabara, kuwabara..." even in English.
If only more creators had this kind of balls.
Though if anyone cares, here's an article on the localization, written by Blaustein himself. Archived, of course.
It's worth remembering Kojima was such a control freak that he literally taught himself how to code so he could have total control of the timings of triggers, audio, etc in Policenauts instead of telling someone what to do and they interpret it. I can easily believe this.