The first Halo was rated T.

Decision by the suits.

This happens in movies too, it's why almost all big action films of 00s and 10s have been PG-13 or PG, even if the preceding films were much darker, or the source material a good match for an R rated product.

It's kind of a shame because it really handcuffs things creatively and expressively. But at the same time : business and the bottom line.

Obviously Microsoft feels that a rating that doesn't advise against purchase for their younger customers is a good thing. Being what it is, it's not a huge shift anyway. As many have noted, Halo wasn't exactly GTA in space. Simultaneously, I am always of the opinion that a darker tone suits big dramatic productions in any case, as long as it's done with gravitas and not cheap exploitation.

Take a great film such as The Dark Knight. Now quick, imagine a totally cleaned up 'PG' cut of it. Lame? Hell yeah. Now imagine an unleashed hard R cut of that film. In my opinion, that's what it should have been (and many MANY others over the years).

My feelings on this go the other way too. We don't need M rated Mario or Minecraft. Things just need to be true to their creative vision as much as possible, and a good match for the themes, characters, and world. I don't think an M rated Uncharted 4 for example, where you really feel the deaths and harm to people, would be a bad thing. In this way, I sort of feel the mid-grade rating ethos where realistic-looking/talking enemies anonymously die in an overly 'clean' manner is more emotionally deadening/inappropriate than seeing someone react with horror, pain, and blood upon being killed in a violent manner.

Just that Halo never was that way.

And dark tone, violence etc. can feel stupid as weell- Tomb Raider 2013 isn't exactly a bad game, but TR being 100% humorless, actually unnecesary violent... didn't make it better. Often felt pretty generic with it's boring characters.

So this game will be like some kind of Sci-Fi Splatoon?

Ever since I've played Halo, I've questioned why it had an M rating.

No it wasn't. XD 

http://3.bp.blogspot.com/-Cn9SwHMIyuA/UX1rzeJ8_II/AAAAAAAADgY/Apgunk9v5p0/s1600/20081009233024!Halo_Combat_Evolved_(Xbox)_Platinum_Hits_box_art.JPG

it was my first M rated game. 

Splatoon is pretty Sci-Fi if you care for the backstory.

And yes, if you're a kid now, you can play legally as the master chief. If you're a squid now, you can play with the Master Chief.

Even Dark Souls 2 rated T you know.

It never dawned on me that the previous ones were M rated. Shows how violent games have....grown...expanded....advanced....?