does survival get harder? in what way?

[jameshello]

hello,

currently my record is 5:00 does it get harder? in what way does it get harder? more zombies? and what is the easiest survival map?

Thanks

[DethPenguin]

Detailed explanation on how it gets "harder" :

http://www.l4d.com/blog/post.php?id=2417

Where you're supposed to discuss the Survival pack:

http://www.left4dead411.com/forums/showthread.php?t=10395