I don't think you give yourself enough credit! Your artwork is good.~ I opened that spoiler expecting a stick figure or something, but hey. Skills. ^^

That was really all I wanted to say, but might as well answer the question--I'm more than happy to use my own artwork, even though I know it has several flaws (and many more flaws that I'm not skilled enough yet to notice). That's the cool thing about art, I think; you always improve, so looking back at your old work you notice what you did wrong and now you know how to do it right. But while you're enjoying your artwork, might as well use it, right?

Honestly your art is unique.

I always think that using our own art can add some kind of identity to our game.

It can also shows an effort, which is a plus thing for me.

So don't hesitate to use your own art! It's good already.

It isn't that exceedingly bad, but I can see it's problems. I know how you feel. I am pretty terrible at drawing and I sort of gave up on it long ago. I am not going to sit here and make believe that everyone can draw well if they try. Some people, me included, just don't have the manual dexterity to draw. No matter how interesting an idea is and no matter how much you embellish it, if you can't draw the lines you want to it's always going to look amateurish and off. Maybe you just need practice, or maybe you will never improve, I don't know.

My advice to you though is thus: Try making art without drawing it by hand. Whenever I feel like making some art, I tend to turn to pixel art or a vector-based art program like Inkscape. It's much much easier to work with a grid, or to work with creating shapes out of line segments you can move around and change. Just because you can't draw on paper all that well doesn't mean you can't crate some wonderful art! I am not saying you should abandon drawing by hand if you think you can get better, I am just pointing out there are other was to do it.

These are other mediums and require a different skill set, but maybe you could do it another way better. You can still use hand drawn art as a guide for your composition, but if you don't feel it's up to snuff, try something else! Try all sorts of other things, and see what works best for you! Some people are good at other kinds of art besides drawing by hand, and I don't think everyone should be required to make art the same way.

Also: You could also try drawing in different styles! Maybe a more quick super deformed style would work better for you. Don't feel you need to do an ultra realistic detailed style all the time.

Honestly I agree, you have some skills. I can see where you have trouble with the light source (A really big issue for myself as well), but you have the concept of how light effects your characters down, now you just really need to adjust which parts are lit. You'd be surprised the number of tutorials you can find online or videos of people drawing.

What really helped me build up my level on art is just using those tutorials, seeing how people do it and mimicking. Eventually you'll be able to pull together all those little bits and pieces into your own art style, which again I have to say is already really good.

I can promise that if -I- can pick up how to do art, then anyone can, and you already have a great basis to start with. Good luck!