Zygote: this is taken right after paternal (dad) pro-nucleus entering the egg.

This is still an one-cell embryo (instead of 2-cell embryo). The cleavage in the middle of the embryo is pseudo-furrow although it looks like cell border.

The yellow bumps (showed as white in the original image) in the embryo are the refractile cytoplamic organelles. They move around as the embryo divides.