The AC1/2 code was a pile of poo to be honest, but it still managed to do many things light-years ahead of other piles of game code poo at the time. Great concepts, but questionable execution (many people, many of whom were brilliant but this was really their first software job of any sort, came and left over the 90s, leaving their code behind. The AC1 software-only (i.e., pre-DirectX/OpenGL/GPUs) renderer and physics code were in large part incomprehensible, but they worked.)