I have just recently completed the  expert realism achievement and I thought I'd share a few survival tips that I've learned on the way of my six hour adventure. ( Yes it took me six hours )

Ok first of all,  as much as you love to have a melee weapon and such. DON'T. Replace your melee weapon with the Magnum. The reason why is because in expert realism the regular infected usually take a ton of bullets to go down unless you're always aiming for the head which isn't realistic when there is thirty coming at you from all directions at once. But when you use the magnum its a one shot kill. no matter where you shoot them. Also when you get incapped you can blast the horde off you in seconds, rather than shoot an entire clip into ONE infected with the pain in the ass pistol. Trust me on this guys in Expert Realism you want to keep everyone as far away as possible. So ditch the Melee weapons for a bit.

Second thing which I'm sure you all know by now is, Boomer Bile.  Boomer bile is extremely useful but provides more help when you hold on to them for more important events, examples when you have to deactivate an alarm, or for an finale when waiting for the escape vehicle to come. Also I can't stress this enough DON'T BOOMER BILE THE TANK. It does absolutely nothing to him and when the bile runs out, you have a horde AND a tank to deal with. Just cocktail his ass and unload EVERYTHING into him, Another thing with the tank is when he throws the floor at you, the *** thing is like a homing device on your ass. The slickest way to avoid a rock to the face is run one direction as he's picking it up and a split second before he throws it run the other direction while jumping. Trust me, it works.

Third thing that I noticed is helpful is the AI...I know what you're thinking " But Bullet the AI's Suck! " Well...yes and no....Yes they are retarded at times when a horde is attacking. Even more so when a teammate is down and they try to pick them up as 50 zombies are punching them in the face then THEY'RE down. Best bet....you hear that horde music, hug a wall. But the perks of having AI's on your team is that they take out the special infect so easy. I can't count how many times I've been pounced by a hunter and less than a fraction later the hunter is dead causing me no damage. Also they find items faster than you sometimes. I'd be walking next thing i know my AI's have shots and pills which is great cause they give everything to you the second you're hurt. Last but not least....they stick to your side. and this is VITAL in surviving Expert Realism. Nothing more annoying then playing with people, turning around, and NOONE is following you, everyone is off doing there own thing, but of course the second they're down they want you to help them.....yea right. Trust me folks. I did 95% of Expert Realism by myself with the AI's. It works. Just learn the system

And Finally. The Level you choose is important. Obviously you're not going to do Hard Rain on Expert Realism, unless you want aneurism.  I beat it on Dead Center. I think it's the easiest of the campaigns.

Well I hope these tips have helped you in some way. Thanks for reading !

If you have any questions feel free to contact me!