Did you click on the higher difficulty?
I know its a beta but I'm hoping there's going to be way more to this game once the full game launches so far the missions seem pretty much the same, even the side missions I did were identical and I'm still not sold on the balance of the multiplayer, I've been looking on YouTube and there seems to be some confusion as to what exactly from your single player character transfers over. I've also not yet found a better weapon than the original one as its the only one that's full auto which I feel is a must for mp. I also personally think they should have kept the vehicles out, I suspect or hope there will be stuff to help take them out.
I look forward to more maps and game modes but if it turns out a grind the game to have any chance in mp then I will be dissapointed. At this moment and I assume its probably made that way the mp seems a tagged on after thought.
The last thing, also not probably good for business is this should have been next gen only IMO.