Numpty Physics by Tim Edmonds, Thomas Perl and contributors. GNU GPLv3 or later; bundled Box2D, glaserl, TinyXML2 and other dependency notices remain in corresponding source. Original authored levels and drawings retained. Browser changes direct player drawings and recordings to /saves.
Upstream revision: ac7e9252bae2494ce2f72ef7dfce451523c3ab6e. Original gameplay, maps and artwork retained. Browser integration by Leaf Arcade, GPLv2 or later. Full adapted source and changes: source/.