I though your tree simulator was an interesting idea, although I was confused most of the time when I played. I wasn't sure what effect I was having on the system. I do the potential for learning about plants in this. If you can figure out to communicate what is going on clearly, then others who play may enjoy learning about how a plant lives.

This is a creative idea! Looks simple but I can tell the amount of work that goes into these kinda things not to mention imagination and some biological knowledge.  I would like to see where you take it.