a grammar mistake so elementary
A grammar mistake according to what?
"Go for It! Goemon" is a wrong translation error
A translation error according to what?
Those are honest questions.
You seem to have found the absolute translation manual and the definitive grammar book of a finished language written by a perfect authority, so I'm interested in knowing what are your sources.
In any case, the English language is still alive and evolving. One should only care about style. If the author prefers it that way, you'll have to accept it, or write your own shit; the most popular version will survive longer, and the other one will be seen as incorrect grammar/translation by future people like you who thinks that grammar is fixed forever. Maybe your own son will see one day "Go for It! Goemon" as the only correct translation and will be ashamed by your posts.