From mastaba to step pyramid. M1-M2-M3-P1-P2. http://www.touregypt.net/featurestories/dsteppyramid2.htm
A couple of years ago (Nov 2015)Scientific American ran an article making the case that the most significant innovations of the Egyptian pyramids were not technological but socioeconomic - the economic organization involved was new under the sun, and made a much bigger difference in the long run than the technological advances required. Whether the other pyramid builders required, or developed, such innovative organizational advance doesn't seem to have been thoroughly researched.
In light of Gobekli Tepe, I don't know of such an innovation was unique to Egypt. Just that it finally stuck.
