I was thinking, would it not be cool if the game had a nice fog effect for some maps? (Or area's of maps?) Imagine a large alien looming out of the fog and taking a swipe at your head, or becoming quickly lost and seperated from your team mates to await your death by alien hands!
If this gets in, it would also be cool if a type of alien could create fog in smaller rooms and corridors. (Maybe as a replacement for adv basi gas?) This would help smaller and stealthy aliens attack humans, or hide smaller bases. Its a bit of a give away that an alien is around, sure, but where?
Presumeably, if its going to be a new type of alien then it would need some new looks aswell. It could look slightly like a mara but it has a flatter face and a bulging sack of fog gas stuff attached to its stomache or back. Killing one could release the fog in a small area. (Could be stage 2 or 3. Or more if thats a thing)
Helmets could decrease the effect of the fog and the normal radar will help you pick out team mates and aliens.