This was really enjoyable! I liked brushing on a lot of clouds and watching plants grow, then adding lots of herbivores and watching them spread, and so forth. Really relaxing experience in a jam-sized package.
If you want to improve on this in the future, I think some more camera controls would be cool: Being able to fix the camera without having to hold RMB, maybe a slider to control the speed of the passive rotation. And also a way to zoom in to see your little creatures on the surface. Maybe even click one to have the camera follow it around?
Overall though, I felt it captured that chill, Bob Ross-y feeling of just kicking back and having fun on the canvas. I'll be following to see what you come up with next. :)