I think you chose cute subjects and an interesting concept that makes for very challenging pixel art to practice on.
To help me explain why, I worked out my own version for comparison. I’m aware not everyone wants unexpected depictions of their pets from strangers, so no hard feelings on my side if you prefer to skip it.
This isn’t exactly good pixel art, which exemplifies how difficult the subject is. Your drawing has a cozier feeling than mine. My detailing is likely wrong. I had to guess without reference where feet and spines would be.
The thing is I initially guessed your duo was a bat and a rat, not two cats. On further study, I can’t figure out what Carrie’s body positioning is, and the purpose of the large pink spot up front is a mystery.
The smaller the canvas, the simpler the subject needs to be, unless the pixel artist is strong on advanced technique.
My pixel art skills feel mid-level at this time. I didn’t use the strongest techniques for two contrasting figures for such a small canvas. An masterful drawing could use dithering to define the shapes or reduced the two cats to simple cartoons.
What I tried to do well enough to demonstrate: color balance and careful pixel placement to define features.
A common trick is to check the readability of the image by viewing it at its full size. You likely don’t want half the image to disappear into roughly the color swath.
Do it look like a pair cats, or whatever it’s meant to be? Does everything important come across? If not, change the pixels.
Anyhow, my suggestion is to draw Harry and Carrie separately. Draw them at different sizes. Get a solid feel for their features and how each works in different settings, assuming your game backgrounds won’t all be the same.
You’r at a good starting point.
