If you're going to make large scaled pixel art, you must resize the original tiny image only by 100s like 200 or 500. If you resize it by 135, 110, 720, etc the picture will come out blurry.
Your art needs more attention to detail, so far most of the pictures you drew for this series have no setting, which it makes it look like they're in a void. Other than that; the character design and choice of coloring was good.
You've got lots of potential I suggest you learn 1point, 2point, and 3point perspective, It's a life saver.