I finished the Environment course, which I have found very interesting, useful, and fun.
My computer did not share my absolute enthusiasm and went on strike while adding the last things here and there, but I even finished the animation with lots of patience 
(clearly, I need to apply the newly learned skills to optimize meshes a bit, to start with!).
I have a to-do list for this one, and cannot wait to improve it, but off it goes for the moment!
Next course in the list is the Characters one 