I know some of you must remember Yahtzee's review of Resistance 3. In he, he pokes fun at the fact that the game shares a LOT in common with Valve and Half-Life.
Well, the link goes even deeper it seems. Before the review was even made, there is a direct nod to Half-Life 2: Episode 2 in Resistance 3. In the level where you're in the minds, there's a flooded room with some lockers. Take the Auger and aim it at the lockers. Inside you see about eight glowing yellow things with pointy tips. The glow like enemies, but they never move and shooting them with the Auger does nothing. They just sit there. It was then that my friend said, "Hey, they look like that gnome in Half-Life." For some reason, there are about eight gnomes just sitting in a storage locker. I always thought that was pretty odd, and then hearing Yahtzee's review blew my mind.