Overall, your drawings depict human anatomy pretty well, but here are some more specifics...
The Harpy: You executed the character very well! I'm not sure if you're done with it, but I would add more detail to the feathers, particularly the tail. I think the talons could have had more detail too. Her hair also seems a bit too big & fluffy, but maybe it's the angle.
The Zombie Girl: I absolutely love zombies & drawing them, so I really like this! There seems like there needs to be more wounds, blood, & guts in it though. If I were to cover up her face, I wouldn't really be able to tell that she was a zombie (aside from the stance). She's also very healthy looking for a zombie & the right leg seems off. It should be a bit bent & the calf should run a little lower. Her arms also look very long.
The Hands (6/100): Hands are super difficult to draw, considering the many many bones that are in them. It's good to have practice. The only thing I can suggest is that you should draw the fingers longer; they seem like baby hands since they're so short!