This is a very old project of mine, which I worked on when I was about 17 (in 2010). It was supposed to become a tower defense with a theme of natural elements for towers, but because of the persistent non-ability to finish projects, that terribly plagued my early programming years this also came to nothing. This project was one of the prettier ones, so I decided to put it on my website and subsequently on here.
Sadly though even after quite a while the framerate is just as it was 5 years ago (~30). I think this is mostly because of a lot of overdraw in the trees, though the pixels drawn there a not as expensive (this should be benchmarked) and definitely because of a huge number of draw calls, so I'm pretty sure significant gains could be achieved with instancing. Also the trees have a lot of polygons and I think some form of LOD should be used, if that could be achieved without being too noticeable.