Oh - there is no liquid water at the alien homeworlds, so their craft is not designed to withstand humidity - so hull damage above water will cause disintegration of the entire vessel!
It all makes sense now =D
You do realise that with the speeds they're coming in at, they probably shouldn't even exist regardless of the surface they're landing on, right?
Though, given that they seem to do absolutely nothing in the time it takes us to get our sweet little arses over there, assuming they were knocked out and are still only just conscious probably wouldn't be all that far off. Gives them an excuse for not hitting the broad side of the barn they're standing in.
The number of enemies in a mission could also rise as more would be invaders come to and grab something to fight with. Of course, there would still only be room for so many of them in a single craft and a few probably wouldn't survive the hit anyway.
But if the player is fast enough, they might even get to nab one or two before they wake up. Though, I think that might be taking it a bit far. Capturing already seems a bit easy.
And I don't really expect them to last all that long in the sea if they're awake or not. Their ship is at the bottom as well as most of their stuff, most like. Harmless. Local forces can do just well.
