Here is a hack which changes all the graphics and sprites in Super C.
Super C (USA).nes
CRC32: 1AC846F0
MD5: 5FEF80625F484FCA06FDB58EBFF9D8BB
SHA-1: 32F706C6222E7EC877C08A1ADC6B7C7BBB69F3DA
SHA-256: 9D2F1935C8AFDB9EEA1C4D983AA750680C99564CBD35978205C34433A46DAFAF