L4D 'Zombiecidal maniac'

Well I've been on my "Zombiecidal maniac" achievement for quite some time now which is the achievement for finishing a campaign on expert (all four levels). I usually play on expert, and it seems that the tanks spawn god awfully fast usually on the second or third part of the campaign which I never have a good strategy when I least expect it. So, my question is could I switch it to easy just to kill the tank then switch it to expert to finish the achievement? Or what would be the best method? Any advice is appreciated.

 

You have to play all the levels on Expert, I'm guess your playing online? If your not you really should its so much easier.

The easiest level to do is probs dead air, the easiest way to kill the tanks is just molly and run. Oh yeah and if u didnt know the best place to finarly dead air, is behind the plane against the body of the other one, when u get tank just molly and run round the plane.

 

I'm not playing online. You need to play atleast one level on expert for this achievement. I've tried to do it in dead air, but it seems every time I hit level 2 or 3 I get bad tank spawns. Is there any way to glitch tanks so they do not appear? Because I've done that a few times where the tanks do not appear which is quite weird if you ask me. You hear the music of when a tank starts to spawn, and the music goes away as well as the screen shake of it running.

 

I think if you get a tank spawn, but you dont start it, after waiting for so long it dissapears.

I remember on death toll there was a glitch on the final level were you could go stand on the left hand side rock in the water and switch off all the flashlights and the horde/tanks couldnt see you. You heard the horde music and the tanks, but after a few mins they all disappeared and started the last wave.