The description of the "Recruit" difficulty is: For people who are new to First Person Shooters. For those of you who are experienced you may find it a little too easy so you might want to step it up a notch to Regular which could be considered as Medium difficulty. Complete the campaign on Recruit to start off with so you concentrate on enjoying this game, the awesome storyline and graphics. If your really looking for a challenge then you can try it on Hardened or Veteren but you should get used to the game first. I suggest you complete the campaign before going into online multiplayer. You will obtain easy achievments along the way and finally complete all three acts which contain missions which make up the full campaign to get this achievment. It's one of the best storylines out there in my opinion so enjoy it.