Just looking at videos I have some ideas, the main problem I have with it so far is that it doesn't seem to encourage creativity enough, I think parts should be made more open ended, for example that spike on a rope part, instead you could have a spike part and a coil part that extends whenever it's squeezed and retracts when it's not so one could assemble the same thing with some muscles, bone, spike and coil and more improtantly you could also use these things for all kinds of weird creations that aren't proscribed or expected by the creators.

Also the nutrient system could use some complexity, for exsample energy uses nutrents to recharge, more than one kind, organs, I imagine you could dissuade use of ranged attacks if you needed to launch things with cost.

Also this:

https://www.cell-lab.net

I like this

Hey, thank you for suggestions!

These are cool ideas, willful deformations of Sipho could add a lot of undiscovered synergy between parts.

Talking about existing parts, we designed them with idea that each could do it's own job and be inherently useful without any other part. That keeps complexity low and helps to learn the game and does not require additional step of finding another part that might make another useful. Bonus/emergent synergies between parts are also our goal when designing one.

Since we had base zooids for breeds in place, we have allowed ourselves to make wackier parts, like grappling hook or energy leech. So we might experiment with things like you suggested.