Nintendo's measures included surveillance of the target. It included going through his work history and may have extended to surveilling family members etc. This also isn't the first time Nintendo has been accused of something like this.
Before the approach was made they attempted to find any other material they could use as leverage. This is deeply unethical and wrong.
It would be one thing to do this in the natsec context, where such an approach is understandable, but it is another for a private company to surveil and intimidate someone who has legally purchased hardware. Video games are amazing entertainment and (sometimes) art, but their importance in the big picture is out of sync with the disproportionate nature of these measures.
It might be of interest to HN moderators to replace the twitter link with this,
https://torrentfreak.com/nintendo-conducted-invasive-surveil...