What your describing are the artistic choices you would have gone with.
You should ,ake both the eye ball and the pupil rounder. It would also benefit from some dithering in the background.
Also, the top border of the eye lid should have a fixed position.
If you'd improve these things, I suspect it would look very good.
It's shape not look like ball and It looks like bended playing card.
Well, if you don't want it to be round that's fine. But if you'd at least round the corners a bit more, it would look a lot more eye-like. And I'm not sure why you'd intentionally refrain from making the pupil round.
The eye does however not look right as it is. It's not a matter of artistic taste. As it is now, it's "eating" the eye away, rather than covering it. Then the eye magically grows back.
I understand if you don't want to dither, it's not really my style either. But then you should avoid such backgrounds, it really just looks like three blocks.