Not much changes other than changing the traps, adding a new one and changing textures and layout of BHop. More info HERE. My traps ideas are slightly limited by the confines of the Minecraft 'physics'. The piston and sand one breaks the laws of Minecraft anyway.
Now that I think about it, I am gonna change all sand textures to gravel to fit the 'underground' feel.
I posted a preview of the traps on my Tumblr, HERE!