Here’s what I’m doing for the prototype regarding this. As it continues from the early multicellular prototype, all of the cell types the player has created will be carried over and can still be edited and duplicated like before. The editing is done with the microbe editor except there will be a few multicellular exclusive organelles. In late multicellular the placement of individual cells is replaced by placing down metaballs. These metaballs have a size, position, and parent which define the metaball structure. In addition to that each metaball has an associated cell type. So basically the cell types define which type of tissue each placed metaball is. I’ll keep it simple initially and probably have just two specialized cell types (designated by placing the exclusive new organelles): neurons and muscles. Placing enough total volume of neurons will be what unlocks the aware stage, and for muscles I was thinking that the player could select the muscle type when creating a joint between metaballs, which would have some kind of effect on the joint in the future.
That’s basically how I imagine the base body shape will be done even once the late multicellular is no longer a prototype. This model doesn’t address blood vessels or any kind of systems like that. I think we should probably leave designing those parts of the game until the basic metaball based editing is done and we get feedback. We should carefully balance how many systems the player must juggle at once in the late multicellular stage, it should not be overwhelming.