Below are a few of my favourites, and just a sampling of the hundreds to be found over at TGAFC,C.
Shadow of the Colossus (PS2), Katamari Damacy (PS2)
Two of my favourite games for the PlayStation 2. In both games, you control a positively tiny protagonist and the overall theme is one of largeness. Each of these covers emphasises this by offsetting your character against a backdrop of a massive Colossus\Katamari of which only a portion is shown. Both Colossus and Katamari seem overwhelming to the point of being nearly insurmountable.