Zombies is now round based and you can choose to play Solo or with a Squad up to three buddies or randoms. There are some very specific achievements we need to focus on as well as some general ones that aren't as difficult to earn, just grindy.
As you play the game, Elite enemies will spawn. For Liberty Falls , the only enemy that counts towards this is the Abomination. They spawn around Wave 15 and then occur every few waves or so. They're quite tough so make sure you use your Pack-a-Punch weapons on them.
If you hit its eye, you'll earn Critical Hits and kill it much faster. It will attack you with a beam attack, this is a great opportunity to blind one of its eyes even though you will take moderate damage. Be cautious not to get swarmed. There's an option for this on Terminal but I haven't played that map yet.
I'll update this guide once I do. For context, it took me about hours to earn this achievement. Depending on how long you survive on each map, you can except to earn about Elite enemy kills per match. This game does have Achievement Tracking so don't worry about losing progress at any time. I am uncertain how this works in Coop , I assume if you either do the most damage to an Elite or get the final kill, you'll earn a tally. Let me know if I'm mistaken here.
Click HERE to access it. All credit to TA user henryr. You can find what's called a Mutant Injection in either the Mystery Box or from zombie drops. You can also find it in the Bank Vault and get it from Rewards from S. They cost Salvage to make so you need to wait a while in game to access it. It might take multiple Injections. It took me three attempts to earn kills. If you combine this process with the Melee Macchiato, you'll get it very quickly on later waves. There is a very grindy achievement by far the most time consuming in the game called Cyberized where you need to Research all Augments for 10 Items in Zombies.
