My estimation is that the break even point for Killzone 2 is around 2 million copies, so I think 2.5 million would be a commercial success (25% ROI). That's the only important measure.

Seeing the hype and quality of the game I would be dissapointed with sales under 3.5 million.

3 Years Development time and only 25 percent ROI

Would have been better off in a bank (Not Lehman Bros)

You beat me too it BengaBenga, I was about to post something similar. Given the games budget it would probably have to sell at least 2 million units to cover its budget. 2.5 million to 3 million would make it successful from a profit standpoint in my view. I know what you are thinking, if it would break even with 2 million, why would need 2.5 to 3 million to be profitable? Bundles. The game is most likely going to be bundled. Bundles reduce a games profit margin significantly.

Ehm a bank will at max net you 5% a year, so in 3 years 5.15%
Investing in shares/bonds will likely net you around 10% a year (not this year though...) so in 3 years will be 13%

25% ROI is over the complete development cycle so is discounted over 3 years.

I predict that even if it sells 800k first week, a very good figure, the forums will be filled with "Killzone 2 flops" threads.

The rumor was that it cost 60 million dollars to make.

Any less than 2 million is a complete failure.

Can't see that happening though. Previews and the small bunch of reviews have been positive.

Well I hear they're going to have bundles so there goes that idea...

What do you mean by "no other games worth discussing"?

What about:

Pffftt... so out of touch with reality.

EDIT: I'm obviously late in this topic and haven't even read your whole post, but your opening argument was too much

It really depends on how much development +marketing +distribution costs are. They need to surpass their investment. Once a game is profitable, it reaches "good sales", but it is a "hit" when it sells double the investment or better.

Of course to the gaming world, it doesn't work that way, but remember, its still a business.

I think it needs 3 million at least to justify the budget, time, and hype for this game. Anything less and it becomes another ps3 game to do ok, but fail to live up to its perceived potential.