Mainly this is a very good game, allot of fun to play and so on, however, i was slightly disappointed, that certain unlockable aspects of the game are not available to be unlocked after the main story is completed.
Though this makes the game more realistic, it is irritating and, mercs isn't meant to be realistic, its all about blowin stuff up.
Finally it seems that play have let there delivery slide, as it now seems to me that they are not dispatching pre-orders early enough to ensure they arrive on time.
But don't let this put you off the game as it is allot of fun and though the unlockable issue is annoying, this is the sort of game that you could happily complete again.
I would also like to to comment on some things said by others,
Firstly the aiming system is very good, sure its not as good as cod4 or the likes of that, but its third person so what do you expect,
Also there are a few glitches and minor things the makers of the game have overlooked, but however these are not really a problem as they can be quite amusing for instance when jen (the female merc) is refered to as "he"
Overall, good game, fun to blow stuff up with your mates online.