To make sure the action never stops, the team made invincibility always enabled (hardcore fans on PC shouldn't worry though, the producer assured me a simple ini edit should be enough to disable it - he said fans will now what 5 letters to look for, beware however, as doing this will disable achievements).
Now, while this means the player can never die, it doesn't mean he can't take damage! The more damage you take, the more red the screen becomes, and the slower you move - you can get as slow as 50% of the default speed!.
This makes it so that the classic element of trying to avoid damage is still there, but you won't have to worry about about it too much, allowing you to focus on the killing instead!