This is Paradise, a 64 kilobyte realtime rendering demo made in 2004 by rgba demogroup (rgba.org) for EuskalParty in Spain. You can download the demo and run it yourself here: rgba.org/prods/rgba_paradise.zip It's made in C (Visual Studio) and uses OpenGL and shaders, but it only works in Windows. Everything is procedurally generated, that's why all textures, 3d models, music, animation, scenery, postprocessing and rendering engine itself fits in only 50 kilobytes.