Eggplant are best when unripe. You should pick them while they're still glossy. Once they start to lose the gloss and turn a bit more dull and matte, they're ripe and are going to be a bit seedy and probably a little bitter. Yours is probably ripe and past peak. I find they still work really well in pasta sauces, less good for a straight forward saute.

Shape can be variable. That's totally normal.

Agree with CaraRose,
The one in the first pic is probably way over done. It is supposed to be BLACK( or dark purple) not brown. Probably it has mature seeds and the flesh is too spongy. .

The second one, colorwise , seems to be ok.

its the same one, in different lighting

I usually pick my eggplants when they get no bigger circumference than a softball.

What about green streaks on the eggplants, is it a sign of being under-ripe?

I think you got some crossed seeds. That does not resemble a Black Beuty.