It takes guts showing off old work - I know I wouldn't do that. But then, I used to draw blobs. Well, they were people, but they came out like blobs (and that was only 5 or 6 years ago for me). And my guns still look like these guns unless I'm drawing a MAC10, only gun I learned to draw. XD
Excellent progress for 4 years. Keep it coming, because when you stop for long enough, you don't always pick up where you left off.