These days, video games have all but internationalised, and you wouldn't be able to recognise a modern game made in Japan by its dialogue alone. But that wasn't always the case, and it would be a perfectly common and accepted occurrence for games to coming over from the far east to contain some typos that have since gone down in video game legend, forever immortalised as memes.
This was back in the days before many Japanese game studios had the budgets for proper localisation teams, and in order to ship their games out quickly to the west they'd just grab the nearest kid with a high-school English qualification, get them to scribble down the game dialogue, then classify their crude but hard work as 'work experience' so they didn't have to pay for it. Okay, this exact scenario probably didn't happen, but judging by some of the legendary translation fails out there, we can safely infer that making in-game stories legible for English-speaking audiences wasn't a massive priority for Japanese publishers.
Not that that really mattered, because back in the days of the NES when many of the greatest mistranslations were made, stories just weren't that important. And without shoddy localisation work, we'd never have got great characters like 'Bimmy and Jimmy', or memorable phrases like 'A Winner Is You', would we?