I like the theme and the way it works, but I definitely think it should be balanced a lot better, for difficulty, it didn't take me too long to get the "ludum tree", and then it can be sold for quite a lot, after that it's very quick to get all of these trees planted and there doesn't seem to be anything else to do after that. the co2 doesn't increase any more and there's no more challenge. I suspect you probably wanted to do more tree types, and ability to plant more trees, and have the population increase match the co2 increases for more difficulty. If that all kept up, and you could expand, it would be much better. I just tried it without planting any trees, I got game over with a max population of 181, but the co2 level wasn't even half way full, I assume you had problems with the meter. But I like what you were trying to do and I have no idea how to code, so I imagine getting to the point that you are was challenging enough.