There are definitely going to be more new THINGS than what little they've shown so far, that's clear from the interview.
Not to mention there are (at least) five months of development left for things to be improved and added, so I see no point in complaining right now.
Those icons really aren't that clear. It could just be a guy with a gun. You know... the guy that survived. As in the part that you think might be a wheelchair could just be a shadow.
Might I also add that such things as mutagens do exist. Mind you, none exists in reality that could cause the complex changes that would be required in L4D and other zombie media (without outright killing the host), but the possibility is not entirely out of the question - just very unlikely...
Bah. I rarely ever shoot someone (unintentionally). Knock zombies off people with melee, and be aware of your cone of fire. Aim high; not only does this get a nice few headshots, but it wont hurt your buddy on the ground. I've had rounds on expert where I managed to get through the apartment map...
My friends and I have noticed that, on occasion, the witch, after killing the person who startles her, will simply run away, hands around her head. Makes me think she could truly be mind****ed and perhaps partially aware of what's happening (to her). The torture of that causes the secluded...
Mind you, I could be wrong, but I'm assuming those stats will be in the full game, along with the achievements. The demo doesn't track anything because it's, well, a demo.