

Not needed until wave 6, but look for it across your wave. Wait after the choper that firing at you will come NOTE: the chopper that is dropping the juggernaut can't be destroy, don't waste a predator on it. Later on wave 11, you will have to kill 2 juggernaut, and you will have to kill infantries too, so use a lot of predator missile to kill the juggernaut when they're dropping of the chopper. NOTE: it take about 15-20 minutes to reach wave 15. if you have extra money don't be afraid to purhase a self revive, those are very useful when you'll get downed and your teamate is in big trouble. Continue on your way to wave 15, at the wave 11 you'll have to kill a juggernaut, use 5 C4 to kill him, one at the time, wait for him to get back on his feet before throwing an other one.

Most your going through wave, the enemies will give you more money but they're more hard to kill.

at the wave 6 you'll have to kill 2 chopper.Take a predator missile and just kill those, if you are on a map that havea roof on the air support armory stay there and you'll get the achievement to destroy 2 chopper without getting hit, after wave 6 start using your mp5, and swap your pistol for an ak-47, your pistol should be empty. You will start with a pistol (it will change depending on wich survival tier you are, but in the last tier you will start with a m16 red dot and a five seven), for the 5 first wave, use your knife to kill the enemies, 1 stab to kill, at your kill, be sure to take the mp5 on the ground, you'll need it later, use your pistol only if your going to die! don't waste your ammo without a good reason. So, last night i just get my unstoppable achivement, i have some tips to help you guys getting through all of the 14 waves you need to (you just need to reach wave 15, not to complete it, don't misunderstand the achievement description) they're all possible alone, but i still recommand you to get a partner to do those.
