Very sad to har this News, the wait is going to be long now. Can't see this releasing until 2022 now

This is an interesting delay announcement as he went into quite a bit of detail as he basically confirmed a Miyamoto style scrapping has taken place, Retro plus Tanabe's team are collaborating on it. Fair play to them rather than continue with something that they deem not up to quality they're willing to start over I don't know many developers that would do that today.

Rough that we aren't going to see this game for a long time.
But I was getting nervous not hearing any news for ages, so at least they are confirming that the game will happen. Unless Retro makes a bad game and they can it :)

Oh snap! In my opinion, Nintendo really shouldn’t have announced the game so early, Switch was already selling great. 2017 me would slap me for asking this, but I wonder if Retro is still up to the task? It’s been like a decade since the last one. Still more faith than putting it in some brand new hands.

This are actually pretty good news to me.

When I knew that Metroid Prime 4 was in development and that Retro Studios was not the studio behind it, I had many concearns about the project. I wondered if Nintendo was actually aware of the importance of the Metroid Prime series for Nintendo fans. Metroid Prime is significant for us for many reasons. First, is the most "adult" and different game that Nintendo tends to offer. Second, the whole trilogy is regarded as some of the best games PERIOD. And third, Metroid Prime is expected to squeeze the console it's in, offering some of the best graphics on the system.

As such, I was not sure if Nintendo, along with whathever studios was developing MP4, were making "just another game". I hope you understand what I mean.

By making a difficult decision like this... restarting the developing and giving the project to both the original producer and studio that made the original trilogy... Nintendo has convinced me that they know how importan Metroid Prime 4 is and that they understand how great the game has to be for us.

So... I'm sad that we have to wait maybe years to even see some gameplay. But in the end I think it is for the best and I believe we'll end up benefiting from this decision.

I wonder what this means for Star Fox: Grand Prix if it actually existed. Completely trashed in favour of Metroid Prime or basically finished production and releasing in the next few months? Will watch the next Direct with great interest

Very disappointing, but updating the fans at this point is the right move - I wouldn't expect this to launch until late 2021.

I'm not sure what this means for Retro Studios' previous efforts over the last few years. Rumours were Star Fox Grand Prix plus a different project stuck in development hell. Hopefully this means the rumoured Star Fox game is close to completion and the unnamed project (if real) was canned so that Retro can focus on Prime 4.

Props to Nintendo for not rushing out a potentially weak product but restarting instead with a dev that is experienced in the series.

I’m honestly very disappointed. 2021-2022 release date.

Seriously, very very disappointed with the management of the game.

This is not something I was expecting to see.
Who was developing this game initially?