I am trying to get the snake idol,but I have ran to a problem. I have killed the slim and I tried to go down the tunnel behind him but I can't go that way for some reason. what am I doing wrong or did I miss something.

thanks

The tunnel the branches off between the 2 rooms underwater? That slime? That's where you gotta go.. just try swimming around in there...it can be a bit of a pain to navigate, but try swimming directly down as far ..then in a bit further, then down again..if the angle isn't workign for you. There's a room in there that you need to get into that has the idol on a table.