I'd say that you haven't "improved" directly. It looks more like you've developed stylistically. I would still recommend that you do figure drawing to practice (as most people need to do, including myself). Improvement is done, usually, through very intentional practicing. Drawing a comic will help you refine what you already know, but without any sort of intentional practice (focusing on improving hands, or feet, or whatever), improvement will be hard to achieve.
Think of it like learning a language. Unless you are actively trying to teach yourself new grammar or vocabulary, all you are doing is repeating the things you already know. You get better at saying them, but they are still the same things you knew already.
Not only that, it fossilizes bad habits, which can happen in art, too.
My best suggestion, watch some youtube videos or something on methods to improve your art. (I recommend an artist called Sycra). They really help teach techniques or forms you may not have thought of yet.
Most of all, have fun and experiment!