Regarding to my tutorial for building SuperTux 0.3.3 on Mac OS X Lion i updated the tutorial for Mac OS X Mountain Lion.

Prerequisites

Install HomeBrew:

ruby -e "$(curl -fsSL https://raw.github.com/mxcl/homebrew/go)"

Install Xcode

Install needed requirements:

brew install cmake libvorbis physfs glew sdl sdl_image boost

Build SuperTux

git clone https://code.google.com/p/supertux/
cd supertux
mkdir dist
mkdir build && cd build
cmake .. -DCMAKE_INSTALL_PREFIX=../dist/ -DCMAKE_BUILD_TYPE=RELEASE
make install

If all works SuperTux.app should be in the dist folder.