Has a part in game that are problem in tunel. When down the stones in tunel break the game and no loading more.
What I did to correct this bug?

Same for me, wasted my time. The game is bugged in the middle of Episode five when climbing up inside the tunnel collapsing. It crash to desktop.

Quick search, found a way to go through. Gog launch CoJ, in the game folder there is a "CoJ_DX10" you can pass the tunnel with that (you just need to set the graphic options that are reset when launching this executable)

I couldn't get past the same exact section due to crashes, but I just want to confirm that the solution mentioned above works like a charm and it fixed the issue (starting the game with the DX10 executable)