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.
Thought everyone knew this. Kojima has hated every localization of MGS games.
I credit the US changes with at least 50% of the games success. Kojima is a very dry writer, the localization punched up the script and added military sounding jargon. They knew better how to sell the game to Americans than the Japanese did.