Yes, Spore was a major influence, as were Flow and Argar.io.
Regarding the evolution path, my idea was for it to be a quasi-random procedural system tied to the characteristics of the enemies you defeated. For instance, if you ate enemies with bigger tentacles, you had a better chance to improve your tentacles; if you defeated nimbler enemies, you would become nimbler, and so on.
However, there were some basic systems that I wasn't able to include, like your hunger being directly related to your size, and your energy consumption had a heavy increase if you were to actively do nothing.
I do wish to retake this project, but my work-family balance is already too tight to focus too much on this.