I have an interesting idea, after watching the DayZ dev blog working on their motion capture, I had an idea on how a zombie should have the ability to sneak up barely noticeable to the player (crawling on the ground or casually walking) where the player barely notices he or she is being followed. It makes sense if the player does not check his or her surroundings, especially in the woods (where they assume zombies would never venture out very far from the city) they could be vulnerable to a silent encounter. I mean what is more scary then camping in a certain spot and suddenly having a crawler slowly crawl up behind you and start trying to bite or attack you with very little warning. Or better yet, have an animation of the zombie pulling the player down to his face level and trying to bite the player from an extreme close up perspective. Almost like a real time cinematic moment. I think this would introduce a realistic and terrifying feature to the game if the player is too careless, makes too much noise, or if he or she thinks by staying away from urban locations that they are safe. Nevertheless, in a zombie Apocalypse there is no such thing as being truly safe, only a safe state a mind. i also want to add that this idea was also reinforced from one of the episodes of The Walking Dead (season 3) where they parked a car on the side of the road while ignoring a silent and slow moving zombie walking in the background. ...Or if you want, the zombie in one of the beginning episodes in which was crawling on the ground with her hand reaching out. I'd sh*t myself if something like that came up to me unnoticed (obviously from being careless of course). http://www.zombiemojo.com/wp-content/uploads/2011/06/walking-dead-hugs.jpg