How much does a game need to sell to make a profit?

[Zlejedi]

Sniper Ghost Warrior for PC/X360 costed 750k Euro
Witcher 1 was 5-6 milions
Witcher 2 including engine costs and all the preparations for console versions 7-8 milions
Bulltstorm was 20 milions $

So quality of game doesn't seem to be only factor in costs ;)