There are these hidden cellphones which were needed to pick up manually. Now they are auto picked up.
They have also added some bonuses like the first one: 200 health 200 armor (the armor protected against bullets and it was enough for the entire game -> this or the enemies are much stronger now) These bonuses are no longer given.
There is a special zombie type which upon death released a lot of small headcrabs. They just simply die now.
Choppers now require 6 rockets instead of 3.
The game displayed how many grenades I have. It no longer does that.
The companion is nerved. He needs to shoot a zombie 6 times with shotgun at close range to die. He could do that with 3-4 shots.
Enemies are now do much more damage. The soldiers only, zombies remained unchanged. The area where we emerge from subway is very difficult. Probably endgame too if not impossible.
(Written by ModDB user kalixx1)
Well, this new patch has a few differences.