You have now built a basic rig and could happily animate this guy, so you have all the knowledge to go on and rig your own characters.
The problem is this is exactly that, a basic rig. Don’t get me wrong, working through these videos has given you the foundations to now build upon but the rig does have issues.
If you look at the way the shoulder rotates for example, it seems fine around the Z and X axes but when you rotate around the Y axis it deforms badly. Ideally it should twist around the upper arm not the shoulder so in this video we will be adding what’s known as #rolljoints, not only to help the shoulder but the wrist, thigh and ankle too.