Survivor Impossible...?

[Karak]

I've also spent a ridiculous amount of time trying to get the Survivor achievement multiple times. I've started repeatedly, single player and co-op, on the very first level and went on foot all the way through to the Zone Complete screen, on easy, without ever going in the vehicle except on accident, and moving slowly so-as to kill everything that spawns, including waiting forever to kill building using only bullets on foot. My accuracy wasn't that great (57%) since I almost never stopped shooting even when there was nothing there, but the achievement details don't say anything about accuracy, difficulty level, etc. Also did the underground mini-level. Here's my last single-player attempt details (this time I did a small part of the moving wall in vehicle but the rest on foot):
Score: 1127150
Accuracy: 57% 5700
Enemies Destroyed 1043 104300
Soldiers 443 88600
Lives 1 10000
Total: 1510350
Note that I've killed 1043 enemies. Unless there are at least 1700 enemies in the first zone (can anyone confirm this?) then this achievement is definitely FUBAR!

[Karak]

I know some people have got this achievement - but what was done Differently? People said they got it on easy, and on the first Zone. I can't imagine this to be console-specific bug or controller-port-specific either. I'm running out of ideas.

[Karak]

Also for quick reference: Survivor:
"Finish a zone killing 60% of the units on foot."

[unrealbe]

I have the same problem. I play almost the whole zone out on foot. Killed at least 65 percent of the enemies but no achievement.

[smalfri2]

I got the achievement on the very last level, on easy, right after the last boss. You have a time limit and some of the way it forces you out of the car, but my car got blown up a few times so I was running around for the most part.