The CC style on their demo (1989) and first album (1990) was for the most part a half-formed, more primitive death/speed metal hybrid, pretty common for other bands around the US at that time, though there were some touch-ups and aesthetic changes made between the demo and album that hinted at a different approach. The heavily down-tuned "NYDM" stylings were inserted with "Butchered at Birth" (1991) and solidified with the albums that followed. Bands like MORPHEUS (DESCENDS) and SUFFOCATION were already producing material similar to their respective bands' later albums at the same time (1989 - 1990). CC and the "NYDM" bands didn't share exactly the same "scene," either, as they were from Upstate (along with MALEVOLENT CREATION and BAPHOMENT, with whom they clearly shared influences) while the rest were in the NYC/Jersey area. I'm not sure if "rip-off" need be applied for CC as I can't say with any certainty how blatant their borrowing of style was (rather than a simple cross-influence), but implying that the case is the opposite doesn't hold much water either.