First a small plea that you dont answer the myriad of questions I'm sure you'll get that already have been answered a long time ago. Pretty please (:
1. Is it possible to, without having played a single "real" game, jump into challenges and unlock everything from the get-go?
2. Are the "Heckler and Koch" and "Caesar" pistols unique and unaquirable for those who got different packs?
3. Are the "what-if" maps shorter so to speak than normal ones?
4. If I unlock a weapon through a challenge with character X, can character Y use it or do I have to repeat it?
Of course I'm sorry if these have been answered already, I would greatly appreciate someone telling me