1] Melee Blocker Thing - I'm glad they added the Melee Blocker Timer thing. That way, you can't sit in a corner and spam the melee button.
2] Completely destructable houses - I saw a youtube video about a small wooden house with a button to call the Ferry over the lake. In the video, there was no where to hide so you had to keep moving. The whole house got destroyed.
3] Melee Weapons - Yes! I was waiting for this since the day L4D 1 came out. It's about time.
4] Supplies shortened - The creator of L4D 2 said in an interview that you won't find like 4 health packs on a desk anymore. [Except for the start of each campaign]. He said you'll find some scattered out and hidden in places. I'm glad they did this. They made it harder to find it. Not just go across a street and see 4 health packs.
5] Campaigns are 50% longer - Campaigns are MUCH longer then L4D 1. Also, they are much harder like the swamp level. You can go 2 ways. The dirt path with alot of zombies or the river [slows down your walkting] with few zombies. I think that's awesome.
6] New Weapons - AK47! OMG. I love that weapon. If they added the MP5, i'd worship L4D 2

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7] Special Ammo Types - Man. Incenerary ammo ftw! The 'Towering Inferno' achievement would be really easy now xD. I wish they made an Acid Ammo that killed SI + Infected.
Share your thoughts!