To answer the question:
Part of the reason exploitation movies are classified as such is because they use sex, violence or a big star to set themselves apart. They defy genre conventions using these easy ploys. Most games are violent but some use excess violence to distinguish themselves. Dragon Age is a fantasy RPG that uses persistent gore and gruesome decapitations to stand out among many other fantasy RPGs. In that sense, it does exploit violence. Dead Space 2's marketing campaign suggests the game features exceptional violence. I see Isaac's many (enjoyable) deaths as proof of that. An easy comparison is Legend of Zelda and God of War - the combat in both is essentially hack n'slash but Kratos' uncompromising brutality is what gave GoW its unique identity. It's pretty much the equivalent of a slasher flick.
And most of those games where made primarily for said murdering, with story really only there as window dressing. So of these games, what aren't exploitative?
I hope that made some sense.