How about, en route to the Borealis, right as they reach it, they're shot by a blast from a large portal-gun-like device, and transferred somewhere else?
How about this: You can combine your crowbar and Grav gun, meaning you can launch it like a spear, impaling an enemy, and then drawing it back to you in the same motion.
I'd like to see anyone deny how epic that would be.
Combine would be all like "wtf hax", and humanity would be all like "GTFO", and then Combine would be all like "F*** u noobs, we dun need ur crap earth", and then vorts would be like "LOL VORTISENCE."
And then the lack of an ecosystem cahes up to everyone and humanity starves.
So, there I was, playin ep2 on my 360. The part after the first advisor flees. Just as I jump in my car to escape, a hunter rams me... and gets stuck to the car. It was frozen in it's ram animation, and unremoveably stuck to the drivers side. Alyx gets in as normal, and I drive off anyways...