Digital is like 15% of sales, just add that ontop of the sales numbers.

It says a lot about how big an IP Halo is when we can look at 150k physical sales in just the UK and consider it disappointing It'll be interesting to see if this reflects a global trend, or if it's just the UK seeing a drop like this.

I think it varies from game to game a bit too much to apply a fixed amount. Would probably be best to assume something like a 10% to 30% range.

I don't think this is very surprising, most people suspected lower jumbers than other main titles in the series. Halo 4 already showed somewhat of a decline.

8 million is very very generous.  The user base of xbox1 is at 14 million after 2 years.  I'm not sure if xbox1 will get to 50 million user base lifetime.  About 3 years from now, it is very doubtful that xbox1 will be at 40 million.  Assuming best case scenario that in 2018 there are 40 million xbox1 consoles sold, that's a monsterous 20% attachment rate for 8 million Halo 5 copies to be sold.  

- Digital sales definetely influenced these numbers.

- Halo 4 and the mistakes done by 343i may have left an impact on long time fans of the series that decided to wait before pre-ordering this time.

- The market for FPS games is much more crowded now than 2007. 

Games this gen are getting reviewed more thoroughly.  People aren't just handing out 10/10s which is what most of those reviews for the first 4 halo games got when reviewed well.  

The multiplayer is the best since two and the campaign is on the lower end of the spectrum story wise, but still very fun. 

Most people that played Halo 1-3 are no longer playing video games. I'm not sure if Halo 5 has bunch of new fans to replace the fans lost.

I always suspected this would be one of the worst selling Halo's. After so many games in the series you have to expect that some people will get tired of it. I got an xbox 360 just for Gears of War (mass effect also) but after the 3 gears of war I was done. I never even tried to get judgement and I could care less about the new on coming out.

I expected it to sell less than previous Halos. It's fifth in series and many of the original fans must have moved on already. Heck, I bet some of them are senile these days. Also it's hard to jump in now since you don't know what's going on with the story.

That said, sales are a bit disappointing compared to previous Halos but I still expect it to reach huge numbers. Gears4 will probs be lowest selling Gears game, Judgment aside.