Board Thread:Questions and Answers/@comment-30818187-20180903063835/@comment-24941009-20180903082327

Never tried to do so, but I think you can just never click the timeline button (the one that takes you to where you see all the cards, progress and stuff), so that you don't move on to the Creature Stage and stay in Cell Stage. Same would apply to the other stages (although Trival and Civilization would be quite boring to continue after you're done with all other tribes/nations). I don't think you can gain more DNA and grow into a bigger cell as such, though.