Art needs lots of work-good effort and persistance
Since you seem like the person who actually wants critiques here's my two cents.
When people say your art needs work, it means that you need to focus on making your characters more believable. By believable, I mean that the characters seem like they can actually exist in that world. Try to keep their volumes from warping constantly. A great reference for you to learn from is the "Animator's Survival Kit" by Richard Williams. Almost all animators worth their salt own this book as well as any beginners. The effort put into this animation shows to me that you're serious about trying to learn how to animate. Start taking life drawing, etc. Another book I'd recommend to learn how to "see" when drawing is "Drawing on the Right side of the Brain" These are two no-bullshit books that will improve your abilities by teaching you the basics of art and animation. Good luck.