in order from left to right: original resolution, 4x upscaled, 4x with softrasterizer turned off
yeah, that's some *crag*ing HD mario kart DS right there nigga
how to:
1. download newest build from here (windows only)
2. acquire roms
3. do this
4. and this
it's gonna run slow at 4x, but 3x and 2x are faster, turning off softrasterizer seems to tune up to both the graphics and performance, but I don't know if it does this with all games
more pics: