I'd help you, but you're stuck with the PS3...lol well I can give you some general advise. I made it over level 15 by myself on every map. (I also have every achievement)
- First If you complete all of the missions and play a few of the survival maps long enough you should rank up. As you rank up you get access to better gear if you make it to highest level things are super easy.
- Second when playing. You always want to have a self revive. If downed you can kill an opponent or hide and keep on fighting this is imperitive. On maps where you don't start with it it should be your very first purchase around level 3.
- The second most useful thing is the perk Sleight of Hand. which can be obtained through air drop. This should be one of your very early purchases.
- You should also be sure to buy C-4 and flashbangs early on in order to deal with Juggernauts. Using Hit and run tactics you can ambush juggernauts, fall back, and repeat defeating them with ease.
- Learning to prioritize targets is key. Always kill weaker opponents first. Never allow yourself to be surrounded.If you see it happening. Push through the weakest area and break free of their attempts to surround you. Though they will always keep trying to flank you. If done right you should be able to get them to expose themselves and eliminate them from a distance. You should always take out choppers quickly. Stay inside until most of the troops are eliminated. Juggernauts should be dealt with last. They always charge, and are very slow. Even though they are the toughest enemies they are also the most predictable.
- As for weapons I highly reccommend not buying any until around round 6 or 7. Your starting weapon(s) should be good for the first couple of rounds and the weapons enemies drop should be decent enough until then. Model 1887s are decent for the first few rounds. The MP5 will also do you well for quite while. The Ak-47 isn't half bad either. The USAS-12 is actually quite powerful but you'll need to collect lots of ammo from the suicide bombers. The ACR is a keeper. Its high damage and high accurracy make it worth holding on to. The FAD isn't bad but it burns through ammo quickly. The the PM-9 is awful and the PP-90M1 isn't common enough to rely on.
- When buying weapons an LMG is always a good choice - you'll probably need one by around wave 11. They have large magazines, high damage, and high ammo capacity. They are one of the only weapon types that can truely continually dish out consistant damage long enough to last you a few rounds. Buying a grip should also be done early when getting one of these weapons. Assault rifles are generally great but run out of ammo quickly on higher rounds due to enemies wearing body armor. Having an undermounted shotgun can save your life in a pinch. Other weapons can be used as needed but LMGs and ARs should be your mainstay.
- You can use claymores to thin out enemies but do not rely on them, they may only serve to slow down enemies. always make sure you are not endangering yourself when placing them
- use of support can mean all of the difference on some maps. Using Predator missiles or air strikes are great ways to deal with large groups of enemies, helicopters and juggernats but make sure no enemies are close to you while using them. And with airstrikes place them where the enemy is going to be not where they are. The GIGN team can save your life time and time again in enclosed places like buildings. But you must ensure they are not surrounded or they will die quickly. The Delta team can be useful but they rarely survive long.
Hope this helps good luck!
Highest I've made it is the wave where you come against 3 Juggernauts (27?) solo. Survival mode isn't that hard, because the bots are not very good at all.
My best advice is to just run from line of sight to line of sight. Run at a group of red dots, pick an area to headglitch where you can see most of them and kill them all. Then, move on to a different point. Just keep doing that and the round will be over in no time.
A LMG is definitely great once you get to the later waves, High damage and large clips means you can hold off invaders for a while.
I've never touched the killstreaks or any of that stuff, but if your a fan of sitting in one corner and making the enemy come to you, I'd assume a sentry gun is pretty useful