thankyou so much for the feedback and for playing the game. I have now realised that not everything in the game was as intuative as we thought it would be.
those red floating dot are called 'antibodies' and they will attack and damage other cells (kind of like defencive homing missiles). you are correct about there being a size cap for the player, you cannot exeed 80um. also yes, the bigger you are, the more cell parts you can carry, additional cell parts will not be picked up.
thanks again for playing the game, it means a lot to us that people were able to enjoy what we made.