So, I’m not shy about the fact that I’d love to play as a race of macroscopic unicellular people, and to that end, I seriously think that it would be an intereting avenue to allow the player to form unicellular organisms into aware, awoken, and even civilized organisms. Intelligent Unicellular life to this degree is a bit of science fiction, however, it isn’t unprecedented; unicellular, polynucleate lifeforms such as Xenophyophores are capable of constructing nests out of deep-sea marine debris, which one could argue is intelligent behaviour (the shells are formed from pieces of marine degree stuck together with organic adhesive, not grown as a cell wall or membrane).
That said, being unicellular would most likely have some major disadvantages; for example, it would take a lot of membrane for a unicellular species to stay properly together outside of deep, pressurized water, and evolving intelligence beyond basic tool use would be quite difficult. On the flipside, however, unicellular organisms would thrive (heh heh) in water, where they can freely absorb nutrients they need. I’d imagine they’d also have limited senses except for chemo- and electroreception.
Ultimately, this is just food for thought. I hope you have a great day, and thanks for reading all the way though to the end.