1) Beautiful View. Somthing so pleasing to the eye your head explodes.
2) Beyond Awesome. The Truest, and purest form of greatness.
2) "The Last Samurai" was a viewtiful movie.
Source: Viewtiful Joe (Gamecube game made by Capcom)
Viewtiful now meaning, Something or someone that/who is at a level that is so high to call it or them Beautiful is a gross understatement.