Still stuck on level 14.. But thanks  for the help!

Good walkthough! I don't need it, though, because I've already beat the campaign and challenge levels.

WEll Thanks guy it took a bit to write out (:

Well done! I wish this game have a multiplayer :/

you forgot challenges.

Double Agent: a 15-kill death match where teams are randomized every ten seconds, just use your best character.
Kevlar: 30-kill and after every kill you gain Kevlar, go after those without Kevlar.
Golden Gun: pretty easy, the gun is a one-hit kill, you only need one kill per death to win.
Rocket Race: 20 kills with no skills and your weapon is an RPG, use your character with the most health.
Prepared: 15 kills and you wield the m-32 and the most reflective shield, otherwise the same as rocket race
Norris, Chuck: you have to get 25 kills without dieing using a butter knife, try to drop down from above or jump up from below.

accidentally hit submit.
Golf Season you have four lives to get twenty kills. easy way, stand on the far left side of the plane, the golfers will swing but miss, use ricochet as a kill streak, with it enabled you can run up to the golfers and they will kill themselves.
Ninja Assault use commando with belt feed and a high capacity mg, just run around shooting and whenever you spot a ninja finish it off.
Poison whenever you are the juggarnaut you take steady damage, don't let it kill you or it will count as suicide.
Big Brother you have a permanent heli,but no weapon, stay under cover and let your heli kill the enemy whenever they go outside.
Self Experiments this can be hard because of the scientist's strength, make sure you have a weapon that can deal out damage quickly, and only rush when your teammates, who hopefully aren't assassins, do.
Knife to a Gunfight you are an assassin fighting a bunch of stormtroopers with knives, use a powerful sniper, anything above or equal to the dragunov.
Hide and Seek use a powerful weapon like a rocket launcher or the awp, try to avoid commandos with commando rocket launchers and tanks, go after assassins.
Vampires similar to poison except everyone receives damage, try to keep killing enemies as it regains health and don't die from poison.
Meet Your Makers justin has a minigun and blur, mike has spas 12 and a shield, you only need one kill a life and it is easier to kill justin. using a high damage weapon like the awp looks well because you can shoot them before they start shooting you.

@Jason96 I'm aware I left them out I figured they were all strait forward and didn't required a walk-through but I gave tips for the few that mite stump the odd gamer but anyways Thanks for adding this (:

i disagree for what you said for hide and seek. if you use a killstreak like helicopter you can use that to kill the enemies, or you can use airstrike and a rocket launcher.

note for self experiments. you can use sniper with blur, awp, and smoke bomb. you can kill scientists in one hit and teleport the instant you grab the case.

p.s. smoke bomb takes two kills.

@Jacen96 Yes but I wanted to make it so there was no chance of getting killed were as if you do that you have to kill a few people first to get that kill streak. And as you do that you are more likely to be killed.

smoke bomb is useless, as you just move somewhere else, maybe right in front of one of the commandos or tanks. with helicopter it doesn't reveal you and you can just walk right up to them.

p.s. the awp can kill anyone in hide and seek in one shot, you might need to hit the head and it doesn't include tanks.