With just over three weeks to go now til the launch of Splatoon Raiders, and now we've had a good look at it, how much do you predict the game will sell lifetime, and why?

8 million

Honestly it's pretty hard to predict. I think 5 million is guaranteed just because of how strong the franchise is in Japan. Splatoon 2 and Splatoon 3 roughly did 7.5m and 5m respectfully outside Japan so because it's a spinoff I could see it do 3m/3.5m outside Japan, and then a little bit more in Japan.

So something like 7.5m/8m lifetime

Ooh this is a hard one! The game will sell very well if Splatoon 2 & 3 are worth going off of (the latter being the fastest selling game in JP of all time at launch IIRC?). It’s a spin-off title, so maybe it won’t do similar figures to mainline… buuut I know for one that my excitement for Raiders far eclipses that of Splatoon 2 & 3, which felt as though they stuck a little too close to the OG Splatoon formula (in its single-player campaign).

That said: Japan will go crazy over it and it is Splatoon’s debut on Switch 2. So, I will be bold and say 7M by the end of the current fiscal year & +10M LTD. I don’t see it outperforming either of the Switch 1 mainline entries, but it won’t be too far off either. It literally is Splatoon 4 but without an emphasis on online turf wars and such, and with a far more creative spin on the gameplay loop all at a mere price tag of $50USD (digital).

I think the main draw of Splatoon is the competitive aspects. I am more conservative in my estimate. I am thinking I will pick up one of the 3.5 to 5 million copies that will be sold. It has been quite some time though since we had an entry in the series so I could be too pessimistic. Personally I am hyped for a real Splatoon 4. I do hope that we see some of the new saminoids in S4's Salmon Run modes.
I will be picking up Raiders digitally for my wife's Switch 2 though after seeing the direct. The fact it supports local multiplayer and it seems I will only have to buy one copy is what put me over the fence on this game.

Yeah Japan goes crazy for Splatoon, I expect Raiders could be a real system seller there. I'd guess about half the game's total sales will be from JP alone, I think that was the case for prior games IIRC.

In a few weeks Famitsu will give us some indication of the game's scale then.

Well, we have our first concrete numbers; 475k (physical only) in Japan for it's first 4 days, as per Famitsu:

https://nintendoeverything.com/famitsu-sales-7-20-26-7-26-26-first-week-sales-revealed-for-splatoon-raiders-big-nintendo-switch-2-boost/

~7.5m. probably 3-4m in Japan and 3-4m everywhere else. Maybe slightly lower under 7m.

S2 won't have nearly the sales as the Switch so don't expect "the Switch effect" where tons of games sell like 15+ million. Also being single player instead of online match game which is what makes splatoon popular will obviously hurt sales (though apparently it is quite a good game).

Famitsu sales numbers and shipments (470k sell through, 40-60% sell through of shipments) means its very likely shipments and digital sales for Splatoon Raiders is well over 1M in Japan as of now, so WW shipments and digital sales should be around 2M at launch, with Japan maybe being 60%+  or so of total shipments and digital sales. A lot will depend on legs but i think its realistic for lifetime sales to reach at least 5M-6M, with around 50%-60% of shipments coming from Japan.

I want it to sell 20 million copies.

I think it will do 2,5-5 million