1.- I have always believed that if something like the alien queen attack you, you should fly through the sky, and if a bullet hit you, you should feel a great pain and divert your aim
I would like much to the fact that there can be more "interactive" and hard fights, of course in a big difficulty
I explain it: the queen may be able to grab you and trow you or attack you so strong that your aim flyes out, and with the bullets could be the same thing, someone shot you, hit your hand/weapon and move your aim, because sometimes is pretty easy, just run and shot, if you get injured you heal and you kill it without problems.
2.- some aliens and creatures are advanced, and they know that some preys dont see well in the night
i say that some aliens/animals could go to hunt in the night, when the animals cant see, including the player, that could make that others foes cant attack very well in darkness (the marines could have a bad aim in night) and that could make that the player have more concerns in the night
"watch out, the reapers are deadly in night, but giant things are in the day"
The idea of the more usefull journal is very good, the human could put some combinations of surviving teachings