With the REANIMATION+ update, leg chopping has been nerfed for the better. Same with the Portable Light shoving exploit.

Just a quick word before we get to the meat and potatoes.
You will need to change your playstyle.
Don't cry about your playstyle being nerfed.
It was too strong, learn the game again.
This game is in early access, nothing is final and everything is subject to change.
The devs will make the game how they want for the vision that they have.

That being said.. NEW META!

Shotguns. This is what I was wanting. You can now bring in guns of your choosing.
In my opinion, the new meta is bringing in a Shotgun with an Ammo Crate and Scavenger perk. You can bring in a shovel and tree trimmer to chop legs, with the tree trimmer having more range, both needing heavy attacks to chop.

In my opinion the most well-rounded meta build is:

• Tree Trimmer or Shovel
  
• X12 Super Shotgun or 590A1 Shotgun
  
• Ammo Crate
  
• Preferably matched with Scavenger - Expert

Or a more speedrun focused build for 35 shells guaranteed:

• X12 Super Shotgun or 590A1 Shotgun
  
• Two stacks of 12ga ammo
  
• Preferably matched with Marathon Runner - Expert

The only way you're making it out of the match is by completing the main objectives. Everything else comes second. What I recommend if you're playing classic/hard is bee-lining to the nearest objective and doing it as fast as possible, this way you can practice completing objectives fast and efficiently. This makes sure your teammates aren't risking their lives to complete objectives. Practice makes perfect. I wish I could give you every bit of knowledge in my head with all different objectives but it would take hours trying to explain.

My best advice on how to fight zombies is.. don't fight zombies. That's right, just avoid them, CoD zombies loop them and everything. They're infinite, and while fighting them you WILL get hit. Meds aren't infinite, and you need to share. You might be saying "Jaruud, I can't always avoid zombies!" Well there's better ways to deal with zombies if you need to, and for me, those are:

• Portable Radios - Such a seemingly useless utility item, why would I want to create a super loud distracting noise that will attract all of the zombies to it? I thought that too, but now I realise it's the best item in the game. When I see a Portable Radio it's like I found a gold bar. It's a good 20 seconds or so of zombie free objective rushing. Seriously, they will leave the door they just watched you enter to go jam out to some tunes.
  
• Guns - Save your ammo for the zombies that need to be shot, focus on runners. If you have a shotgun and see a group of zombies, aim for the legs and make a bunch of crawlers.
  
• Flying Kick - If it's just one zombie in the way of travel, jump towards it while holding F and you will do a flying kick, if done right you'll never be hit and you'll pass by the zombie no problem.
  
• Leg Chopping - This is still a great way to deal with zombies that need to be dealt with. The power has been nerfed but if you can safely take down 1 or 2 at a time, the safety increases especially for finales and holds like the Pottsville gymnasium.
  
• Drawing Aggro - If you're not good at fighting or doing objectives for any reason, maybe you can't run the game as well, drawing aggro is a great way to help! Sit about 30m or 60m from the objective on a van or somewhere zombies can't reach and fire off a couple rounds. You'll gather a noisy horde that will draw in more zombies, and the rest of the team can complete the objectives easier. There seems to be a spawn limit so every zombie that you gather, is one less for your team to deal with. For people like me that rush objectives, someone drawing aggro is one of the best things that can happen.

For a lot of people, loot is very important, especially meds. Since we can't choose difficulty, a lot of your teammates will be needing more loot than you, especially if you're on a nightmare run with people that have never beat nightmare before. A good rule is a limit of 2. Only take 2 medkits, 2 bandages, and 2 pills to have for emergency. I don't often need to use meds, but when I do then that's plenty for me and still leaves loot for others. If you find extra in places your team won't search, pick it up and either drop it on a path they will need to take (doorways, bridges, etc.) or run to them and give it to them. Same goes for passive items, and ammo.

Take risks, trust me. Run around, take crazy routes near zombies, try to jump on EVERYTHING. Parkour around, try out crazy jumps near objectives. Because at one point you might need this knowledge and understanding to survive. The more you understand about what you can and can't do, the less afraid you will be, and in return you will be faster and safer. I've learned a lot about what I can do with movement in this game, and it's a lot easier than you might think. After awhile I'll update the guide on certain pathing and routes to take for easily completing certain objectives and especially finales.

Unlike zombies, there's only 8 responders. Each responder is important and worth saving. But don't risk your own life to save them, or the team will be missing 2 instead of 1. Share your meds and pills, share your ammo, try to safely revive teammates. This game might be easy for you, but you're not queuing in to "experienced" matches. Especially if it's not nightmare, this could be their first time playing. Understand that they won't be on your level and help them out, teach them what you know. Guide them to surviving what could be their very first match. 40 hours in I can solo a Nightmare, but my first 5 matches I died on Classic. I remember one guy helping me out, teaching me some stuff, and leading me to a survival and it was awesome. Be that person for someone.

Since you can re-roll 3 responders per 50 Credits, just keep going until you get one of these. If you have no credits, you're doing something wrong because I have over 100k.
These are in order from best to worst. If you disagree, let me know! :)
(Info from @SupremeSecretMan/@Sunjing)

• Nurse - Skilled Medic OR Acquired Immunity (Either are good, but you want Acquired Immunity)
  
• MMA Fighter - Sturdy Body
  
• Swim Captain - Thick Skin
  
• Quartermaster - Deprived
  
• Football MVP - Marathon Runner OR Adrenaline Rush (You want Marathon Runner)
  
• Prepper - Scavenger OR Builder (You want Scavenger)

I'll just cut to the point.
There's good skills, there's "bad" skills, and then there's the best skills.
These are in order from best to worst. If you disagree, let me know! :)

Disclaimer: This is not a general tier list, this is meant for this specific playstyle (e.g., speed-run, aggressive, objective rush, solo).

• Acquired Immunity - Even at it's basic, I've been hit THOUSANDS of times and have only been infected twice. Saves wasted time on pills, lets you give pills to other, you're not a burden, and you don't have to inevitably eat led, or your friends.
  
• Marathon Runner - Running consumes less/no stamina. If you can get this at expert, it's a game-changer.
  
• Sturdy Body - Take less damage. The Expert version unlocks at account level 100, showing how good this skill truly is. It was nerfed but this is still a really good skill.
  
• Scavenger - Increased ammo from pickups.
  
• Athlete - Increased stamina.
  
• Thick Skin - More health. Need I say more?
  
• Skilled Medic - This makes bandages worth taking since they heal more.
  
• Deprived - Carry weight reduced, but more stamina and health. Great for an aggressive no-loot build.
  
• Guts - You recover faster from being out of stamina. This can and will save you.
  
• Vulture - Ammunition has reduced weight.
  
• Quiet Steps - This one is interchangeable depending on how you play, but it can help avoid many fights.
  
• Mule - Carrying more stuff is never a bad thing.

• Stayin' Alive - Reviving others faster will save you more than it will save them.
  
• Overkill - Shotguns fire more pellets.
  
• Butcher Expert - Butcher stands above all other melee skills. Although the basic offers no help, expert is worth taking.
  
• Healing Item Stack - Medical items have reduced weight.
  
• Rush - Two-handed heavy melee attacks use less stamina.
  
• Limbo - You hope to never go down, but you also hope you have this skill when you do.
  
• Headhunter - Increased melee headshot damage.
  
• Icarus - Increased shotgun range.
  
• Tight Shot - Shotgun pellets have reduced spread.
  
• Headblown - Extra headshot damage for handguns. Useful for emergencies or extracts.
  
• Adrenaline Rush - If you're in a bad situation, having unlimited stamina is amazing.
  
• Grenadier - Less weight from throwables (If you use them)
  
• Averaging - Headshots deal less damage but body shots deal more damage. Could be really good if you're using a gun build.
  
• Resident Genes - You heal when using pills.

• Hard Blow - Extra stagger for 2-handed attacks.
  
• Foreman - Kicks deal damage to zombies.
  
• Resilience - Reduced damage from environmental sources. (Falling, fire, gas, etc.)
  
• Lucky Pathogen - You take less damage while infected.
  
• Heavy Shoves - Shoving deals damage.
  
• Mohawk - Rifles penetrate more targets.
  
• Wicked - Handguns deal more limb damage.
  
• Doorbreaker - Kicks deal more damage to doors and barricades.
  
• Steady Shot - Rifle recoil is reduced.
  
• Caravan - Extra carry weight, but less stamina and health
  
• Hellfire - Increased hip-fire accuracy with rifles.
  
• Builder - Less weight from utility items (Only works with planks and batteries)
  
• Hitman - One-handed melee attacks consumes more stamina for extra damage.
  
• Steady Hand - Handgun spread is reduced.
  
• Winged - SMG's have increased range.
  
• Penetrating Shot - Heavy Rifles penetrate more targets.
  
• Steel Chamber - Heavy rifles deal increased damage.
  
• Eagle Eye - Damage falloff on Heavy Rifles is never a problem.
  
• Locked On - SMG's have reduced recoil. The only SMG in the game currently doesn't need this skill at all.
  
• Longer Battery - Just turn your brightness up and never use your flashlight unless you really need to.

There are many tips I could share but I'm going to leave out the simple ones like "You can kick down doors" because I think many people know that. If you're new enough to not know that, respectfully, this guide is not made for you :)

• Faster Vaulting: You can avoid the slow vaulting animation by moving your camera away from the vault location, or jumping sooner if sprinting. This way you can just jump-crouch over most stuff and save time. Helpful with lots of zombies nearby!
  
• Bigger Swings: You can hit MANY zombies by swinging your melee left or right depending on direction. This can be used with a two-handed bladed weapon to leg-chop groups of zombies with a single heavy swing. With the 0.4.1 update the tree trimmer still benefits from this, but doesn't work with the shovel.
  
• Security Alarms: In my experience, alarms work in a unique way. Alarms are in every single store or house, with some exceptions being the hospital or bar on Power Plant. Alarms will only trigger when a player enters the "inside" radius. Zombies can break through doors or windows and not trigger the alarm, but once you step foot inside it will trigger. There seems to be a random timer between instant and about 20 seconds from when you enter, so be sure to beeline to turn the alarm off to avoid any extra zombies. The alarm locations never change, so you can learn where they are in specific stores/homes.
  
• Runners: Runners have a tendency to always hit you if you try to melee them. The way to avoid this is using a corner, or some type of obstacle between you and them. They need to wind up their attack, so if they run around a corner they won't have time and you can always hit them first.
  
• Ladders: Simple thing that I see a lot of people not knowing, you can jump off a ladder mid-climb. This is useful to save some time or maybe avoid a zombie camping the bottom of the ladder. You can only jump off from a safe height, so spam space and you'll jump when it's deemed "safe".
  
• Locks: Universe-wise, whoever decided to use these to lock something is insane, they're so easy to get through. Honestly though just shoot them to save time if you don't care about being sneaky. I still see people not knowing this.
  
• Infection: Under 50% health your chances of infection are higher. Acquired Immunity is a must-have skill because of this. While using this perk, I've been hit thousands of times and only been infected twice. Also, if you know you're going to turn, you better remember to have saved a final shot for yourself. Not saving a shot is selfish because your turned character could easily kill a newbie. Always take yourself out before you turn.
  
• Shamblers/Screamers:. Always chop or blow off their frail little legs. With every successful scream, a Runner will spawn and most likely take out a newbie. Avoid killing them because the gas can increase infection if players walk through it, and gas-powered zombies have a higher chance of infecting. (@Manaowa)
  
  
• More on the way! Leave a comment if you have tips.

• @Manaowa - Advanced Survivalist Guide 2
  
• @JAA_007 - JAA_007's CRC Survival Manual [Civil Recovery Corps]
  
• @SupremeSecretMan - 📚 All the Classes Starting Skill // 📚 모든 직업들 시작 스킬
  
• @Sunjing