I think you've done a nice job on the backdrop of the title screen! The doctor sprite on the left also looks quite nice and works.
With that being said, I'm constantly trying to get better at spriting myself, and would like to throw out some things that I noticed that may help the overall quality of your sprites.
1. Your duck sprite is a little pale and light and doesn't really stand out. There are two issues here:
- The sprite needs a fuller outline. In general, black outlines really help sprites pop out. In Pokémon, the outline is not always black (i.e., they'll have other darker colors intermingled with black). This can work but as a baseline I would recommend starting with a black outline and then changing the black outline to those darker colors as looks best.
- Your shades of the same color tend to be too close to each other. I think you have something like five green colors for the head, and they're all mostly similar shades. Alternatively, I would recommend having fewer colors that are more distinct from each other. So, you don't want really light green, lighter green, light green, green, slightly darker green, darker green, dark green. Rather, you want light green, green, and dark green.
Below, I've done a quick edit of the duck sprite. I added a black outline, reduced your green colors to three and replaced them, made the dark brown color a darker brown, and changed your grays to some shades of yellow. Here is the result:
2. Your anatomy needs some work. When you're spriting, it doesn't seem like you're imagining what the object would look like in three dimensional space, but rather you're just filling in the palette with what should be there based on context. So, you know a leg should be below the hip, so you sprite a leg there. An side effect of this approach is that the anatomy of your image gets skewed, because you're just filling the second with body parts without fully considering the angle in three dimension space.
Let's look at the girl for instance. Her top half is mostly fine, but there's some confusion with her hips and legs.
Based on how her hips are angle, her left leg should be in front and towards the camera. You do this well to begin with! However, her foot then bends at a weird angle and goes completely backwards, and I'm not quite sure what her knee is doing. By contrast, her right leg starts out in the back, as it should, but then the bottom of the leg juts forward in front of the other leg. It's almost like she's doing the splits, when you consider the anatomy.
To correct this, I would suggest drawing sketches of your characters first before spriting over them because it's a lot easier to correct a sketch and less frustrating than scrapping a fully drawn body part later on. That said, I think it's still possible for you to edit sprites and combine them, but I'd recommend just being more aware of the angles and anatomy if you decide on that route.
Anyway, hope this is helpful and not too discouraging! Your project looks promising and I wish you the best of luck!
