I think this is a great foundation for an interesting/addicting game! I'd love to see a use for the organisms...like if they had different traits, and you could put them to work in the different buildings you've set up for your base. Maybe they get injured/killed and so you constantly have to upgrade/replace them with better organisms. I think that would help "complete the loop" of the gameplay.
Otherwise, love the art style! Really good submission, nice work!