Castlevania - Symphony of the Night and Castlevania - Rondo of Blood both have about 240 pixels height (Symphony has even less than 240 pixels so it's almost widescreen).
Scaled up to fill the full PSP's 272 pixels height (while keeping correct aspect ratio with black bars on the sides) they both look gorgeous. Simple bilinear filtering does the trick - you don't see any pixels being twice as high or wide as others. There's just a slight smoothing effect, but on such a tiny display it still looks great.
Bilinear filtering on a 19"-LCD doesn't look good. On a 4.3"-display it does.
Recommendation: play Alundra via PS1-emulator on PSP. That's 2D-gaming heaven! (Also 240 pixels height upscaled to 272 pixels height.)
Last edited by john4p; 26 May 2010 at 09:12.