Toolchain? The Xcode/iOS toolchain is about it. I use boost for a couple of things like smart pointers and boost::ptree, and GLM for linear algebra. I'm using GLES 2.0 as my renderer of choice while building this, but ultimately the renderer is abstracted from the rest of the engine so it would be a matter of writing a new renderer if I wished to support a different version of OpenGL or DirectX or something.
The model is from Psionic 3D. I'm not much of an artist so I'm going to have to rely mostly on my internet scrapings for now
The format for the model/animation you see there is Milkshape 3D, though writing a loader for any particular format is fairly trivial. Ultimately i'm going to have to support loader plugins.
Right now the engine isn't doing much beyond loading up the zombie model and creating a few components (render, skeleton, position) and assigning a default animation range. The shadow volumes are computed when the model is loaded and I do my best to avoid triangles that are going to cause problems with the shadow volume (as you can see in the shadow, the tatters on the pants aren't extruded because they make the whole thing look very bad).