I know it's too late for the OP, but here for frugality's sake... The standalone Day Z game will (barring problems) be out very soon. If you're going to be playing that, it makes plenty of sense to cheap out and only buy Op:Arrowhead for now. I think it's pretty fair to assume that anyone who still doesn't have ARMA II - four years after its release - is not terribly interested in playing it. And as for "pretty bad looking textures" and sound, they are the textures and sounds from ARMA II Free, so you can easily try it out yourself (or google a comparison) to determine whether this will bother you. My advice, get OA-only on sale (last year at this time it was $9.99 on Steam, but right now it is $11.99) and be happy. As much as buying the CO package may get you a higher discount, a "deal" is still a waste of your money when it's something you will never play.