Hi Fi Rush success is an outliner

I think being able to pull the "And it's available...right now!" from a big publisher at a big event generates its own sort of hype.

So I don't really know how to answer this. It isn't very surprising at all if it did well, but it was able to do so because it has that sort of privilege.

My answer is no. Hi Fi Rush isn't the first game to come out that didn't get any hype, but turned out to be a huge hit because of word of mouth. You'd only need to look at Vampire Survivors to see another example of that, especially considering there were other games like it before that didn't hit like VS did. The only surprise if you want to call it that, was it being done by a developer known for their horror games. But that is also not a surprise, just look at Guerilla Games. They were known for their FPS, mainly the Killzone series. And yet they were able to create a hit open world game and a new franchise with the Horizon series. There are other examples, but I think you get my point. Now, back to Diablo IV beta :)

Hi Fi Rush has ~300K on steam and got 2m players through game pass I wouldn't call it a massive success, Hi Fi Rush got a lot of noise but wasn't really any bigger.

Game Pass numbers from installbaseforum.com

A Plague Tale Requiem - 1 week - 1 million

Disney Dreamlight Valley - 10 days - 1 million

Ori and the Will of the Wisps - 8 months - 2.8 million

Scarlet Nexus - 15 months - 2 million

Metal Hellsinger ~ 3 months - 1 million

Hi Fi Rush - 1+ month - 2 million