Very polished game. I even loved the little splash animation at the start.
A little biome to much about with is certainly my cup of tea, and I could see myself spending ages tweaking things to see what appears. I echo the same hiccups with others in that Chrome doesn't like to lock the mouse wheel to the game, and scrolls the page, which is a nuisance, and being able to click through on the tutorial would help.
But yes, reminded me of Creatures and Little Computer People in a way!