EP2 for me. It had the Charger for starters.
I liked some of the changes in EP2, like the flashlight being separate from the suit's aux power. The graphics seemed to be beefed up a bit too.
Did you find this small hidden room in reference to Lost?
I've never watched Lost so I wouldn't have caught on even if I did find it. Is it any good? It it uses Half Life references then I'm probably going to start watching it.