Okay, so I played this game, fairly short, on normal. Beat it. Wasn't completely satisfied, so I tried Hard. While in the church room with the headcrab capsules, one of them wasn't completely out of the capsule before he(or she?) leaped at me. The result ended badly. The poor critter was stuck in mid air! What's worse is I got this screenie seconds before he was destroyed by combines (background).

EDIT: It's wasn't just one, but two. The first I killed because He was slowly coming toward me...