There is a memory leak somewhere! check task manager
Check the destructor Physics::~Physics(), it is most probably optimizable
The algorithms and functions are mostly quite unsafe, there should be some more limit checks etc.
Many members, especially functions like Physics::addBodyToWorld(), should better be private. They were made public for quicker prototyping.
double vectors (see note above) The (private) variables SvgLoader::worldBezier and SvgLoader::worldVector could possibly be left out and the data could be directly saved into the corresponding worldBezier2D and worldVector2D objects of the appropriate Level2D object.
Make the SvgLoader more compatible to slight differences in the SVG XML code. It is not very flexible/usable for example when using other programs to generate the SVGs. It should at least be able to take Inkscape (free tool) SVG files.
1.5.4