I didn't like the graphics at all (I see its charm to a point, but too much gore-y and horror for my taste), but when I tried the demo I thought the gameplay was awesome, so: "Soul Sacrifice (Delta)".
Right now I can't think of other Vita-exclusives... oh, wait, after a search I found "Killzone Mercenary", I think it would look great on newer consoles, especially with a remaster, and also "Unit 13", another third-person-shooter that I strongly recommend, it may have its flaws but for me it's good.