The Molecular Stage is an unreleased stage that did not feature in the final release of Spore. Very little is known about the Molecular stage, and it is unlikely that it went further than the conceptual phase during development. It was created on February 4, 2004.
Instead of panspermia (life on/arising from extraterrestrial objects) seen in the final release, the Molecular stage posited that life in Spore emerged via abiogenesis (life arising from non-living matter) following the theory that electrical charges in ocean waters, along with the atmospheric conditions of early Earth, caused certain types of essential proteins for life to be created.
Possible Gameplay Edit
As announced to the public during DICE 2007, the gameplay of the Molecular Stage would have been similar to Tetris and would (presumably) require players to assemble smaller pieces into larger shapes to progress. These larger shapes would eventually form proteins that the player would try to fit together in to create their first cell, therefore bringing the user to the Cell Stage. It is unknown if assembling these shapes in different ways would have any long term impact on gameplay in future stages.
Reason for Removal Edit
It has been proven that the images of the Molecular Stage were just concept sketches. The stage was probably removed because it would require the idea that molecules could think for the gameplay to make sense, so ultimately the designers preferred panspermia as the start of life on a young planet in Spore as it was more exciting.