The sniper bullet hit Gruber in the left side of the head, the side facing the window. When he is shown dead, the entrance hole for the bullet is in the center of his forehead, as if he'd been shot head-on.
When the real Gruber breaks into the hotel room and shoots the two Mafioso-types who originally hired him, the one in the black shirt keeps moving after he hits the floor.
Near the end, Casey is trying to find Chuck. Right before Chuck bangs on the door where Shaw and Sarah are located, Casey is shown at the computer. The message pops up with "Trace Signal Loctated Chuck Bartowski". "Loctated" should be "Located".