Long-time players, I have a question.

[💔ХуйF U C K YO Uхуй💔]

How long did it take you to for the full completion of the Manhattan Project achievement? I'd want to see how your experience was without using any achievement maps.

[🏝️Fersigal🏝]

It's not worth the effort, i have over 3K hours and i have a measily 412.000 zombies killed total. You'd have to play on Unlimited ammo servers on maps like Galleria only for 2K + hours to grind the actual amount.

[I don't remember]

I have been playing since 2013 with some breaks and currently I have 619 478 zombies killed and around 2k hours of playtime. If you see someone with the achievement, they most likely used the workshop map where you can basically go around and do it in a few minutes.

[Analog Horror Freak]

I think it's safe to say that achievement is a joke achievement. The only way I got it, and the only way everyone else who has it that I know of got it, is through a cheese map designed to rack up the kills for you.

[durkhaz]

That achievement isn't meant to get unlocked. It's a kill tracker.
If you cheated to complete it - you no longer have a kill tracker.