because nintendo has it's first shooter

why does mariokart sell way more than any other racing game?
because it's fun

or cs:go as example. that game is also simple and has not much maps, classes, or any other stuff going on.
but It's still extemely popular

this game will sell between 1 and 3 Million lifetime

Some of your points are good. And some of your points suck some major balls. Foist of all, the reviews are good. 4 out of 5 stars seems pretty good to me, especially for a new IP. And while I do understand your complaint about the US price (you and every other motherfucker on the planet), I really don't get this: "Why buy this game over black ops 2 ($20), or team fortress 2 (free), or borderlands collection ($50), or metroid prime trilogy ($20 eshop), or mass effect collection ($5 from flash sale, $25 regularly)?" Couldn't you say that about any game ever? What is the purpose of a statement like that? Of course there are other games with a cheaper price that you could buy. But this game is different than those games and if you can't see that, I know of a few great mental institutions I could get you into.

Because it's Nintendo doing a kind of new thing, and a lot of people, for one reason or another, are really pulling for it. Some of it comes from an honest excitement for the game, but I believe much of it also arises from spite and resentment.

As far as "doing well" goes, 2 million strikes me as just silly. 1.6 million is overly optimistic. 1.2 million...it's in the realm of possibility, but with what we know now, I don't see it happening. 0.8 million is a bit too pessimistic, and anything less than that makes me scratch my head.

@ohmylanta1003

Ok, the reviews are actually good for a game (8/10 is definitely solid). I was just hoping for at least a 9/10 so it could make a huge splash as a new ip like bloodborne or the last of us.

However the content for price is still really bad. Take smash bros wii u for instance. The only alternative to that game is playstation all stars at 720p, meanwhile smash bros is a glorious 1080p 60 fps, 8 player, great online, tons of single player content (even the soundtrack has about $60 worth of songs). Or take the last of us, a single player game whose story mode has left critics calling it a masterpiece. Or watch dogs, which may seem like a gta v clone, but at the very least creates a new city to explore. These are all games that are worth full price upon launch.

Now take splatoon, a game with 5 maps (measly compared to the amount in black ops 2), 1 v 1 ballon popping as its only local multiplayer (bo2 has 4 player customizable games), 2 online modes (bo2 has WAY more), less guns and customizations than most games (bo2 for example), becoming a squid and looking colorful as its unique feature (bo2 has a 4 player local and online zombies mode as a unique feature), a 4-6 hour story (I'd say on par with most games), and costs $40-$60 (bo2 costs $20 and will soon drop due to bo3 releasing later).

This pretty much shows why splatoon is worth $20 (or atleast perceived as a $20 indie game)

Real guns and death are apparently mass appeal.  Makes sense considering how fucked up the world is right now.

It's well advertised and attract both adult and children and it's fun and look like a good game.

it has everything to succeed

The game is excellent. Its sold out in Japan and the demand is there. There's no reason for this argument anymore. It has already shown that its going to do well.

But Splatoon already making huge splash, from reviewers, but mostly from Splatoon players.

Splatoon is worth $20!? And yet Splatoon was sold in two days in Japan and its selling very well on other markets too. Why is that? It simply, Splatoon is worth of its price, everyone who played Demo or game can tell you that, and thats why is selling great.

@Miyamotoo

The reviews as I conceded were solid. But there is no denying the fact the the most recent well known and most talked about ip are either the ones that have very high scores (bloodborne, the last of us) or have an insane budget or marketing team (destiny, titanfall, evolve). So far, splatoon has neither.

How well this game sells upon launch does not really say much. As I recall, pikmin 3 also sold out its shipment early on, but later Iwata himself admitted that Nintendo was not pleased with the sales.

Besides, Xenoblade also had a  really good Japan launch, but the following weeks was selling less than 10k. I believe splatoon will sell 300k-400k first week, 600k-650k first month and 800k-900k lifetime. It will have a good launch (due to wii u owners not having anything for the first 9 months of this year besides mario party), but splatoon will not have good legs (again due to the notion that splatoon looks like an indie game, is marketed heavily towards kids, and has less content than most other games)

I also doubt any of those games will ever reach the sale numbers that Ninty fans first said they would. Bayonetta should be enough prove of this.