KompreSS is a VB.NET-based compression and decompression DLL for Kirby’s Adventure (NES) and Kirby Super Star(SNES). It was based off documentation of the format written by Parasyte. Usage directions are in the README.

UPDATE March 5th: A mistake in my understanding of the compression format has been corrected- specifically, Bit-reversing Lz-Copy was implemented as “Xor 255″ instead of “(B And 128 7) + (B And 64 5) + (B And 32 3) + (B And 16 1) + (B And 8 1) + (B And 4 3) + (B And 2 5) + (B And 1 7)” This has been corrected.