Tearaway (the best Vita game for me), Muramasa, Soul Sacrifice Delta, LittleBigPlanet Vita, Killzone, Doki Doki Universe, Assassin's Creed 3: Liberation, Street Fighter X Tekken, Another World 20th Aniversary Edition, these are some pretty good ones.
Edit: The most visually impressive is definitively Killzone Mercenary. It comes actually close to Killzone 2 visuals, and that game is impressive even for today standards.








