I just think that the creatures should be able to follow you! I've found a trick to make the game much easier just run to the end of a area while the enemy is hunting you, and when you run low on hitpoints move to another area,,, you can rest or heal up in peace and the enemy is kindly waiting for you just one step away!
feature hehhehehhe, maybe if we put is this way, the raptor is afraid to run to close to human civilization so it'll give up hunting you if go in the direction of the city?
This was seen during beta testing and teh solution was to allow them to heal a bit when you exit an area....b4 they would have the same amount lost and you could rest and come back.