Unlike Kodu, Scratch, or GameMaker, Python doesn't have any straightforward graphics or mouse/keyboard handling built in. In order to handle things like that you'd need to install a 3rd party library like Pyglet (there's a Beginners Guide here) or Pygame. There are also a few pre-built engines that use Python though like Panda3D, or Blender which comes with modelling and rigging tool's for making 3D models, although the learning curve on it can be pretty steep. Though not related to Python, the Unity3D Engine is also a popular choice among developers.
I'll be off the grid for a few days, but the important thing in all this is to find a platform you feel comfortable with and go from there, be it GameMaker, Unity3D, Python, or whatever else. Feel free to experiment and have some fun. ^^