Up front, if you just want a quick verdict, I am highly impressed with this bundle. It does however require a great deal of patience and some time to enjoy it.

The single player consists of 2 big, 1 mini and 1 preview campaign, effectively the first mission of PMC.

There are also a number of single missions. The 2 big campaigns, from ArmA 2 and OA respectively are quite different. Where the OA campaign is very nice and worked for me without so much as a hitch, consisting of very nice missions, the ArmA 2 campaign was full of scrips not working and having to restart a 90 minute mission, (most of which are the same search and destroy type missions) because somebody got hit by a stray bullet or or script wouldn't fire. The mini campaign is quite good however also very short, took me 90 minutes to get thorough it.

The single missions are, for the most part pretty good for a quick fix, such as a quick patrol from a to b to c to a in a chopper and kill some enemies while you are at it missions. Or clear the village etc.

I have not spent much time in multilayer and in fact find this game to only be really suitable for single and co-op play, however many others seem to enjoy multilayer greatly