I just thought of how the game could grow into something more serious without changing its principle much.
So, you know that this is a game about colonizing asteroids. With 'seeds'. So flesh that bit out and bring some flavor through. Asteroids are usually one of the three things - silica (rock), metal, and ice. Each such 'group' can then be divided into three subgroups - Silicate could include Rock, Dust and Crystal, Metals can be split into Common, Rare, and Radioactive, and Ice... well, I don't know but something could be thought up, like frozen water/frozen CO2/frozen methane. Now, each of those would contribute to the construction of your 'seeds' in varied ways. Among other things, creating weapons with different properties - lasers for Crystal-heavy asteroids, rapid-fire cannons for abundant common metals, the like.
Another change could be to the trees themselves. The 'seeds' produced would actually be just machines created through inorganic metabolism out of available materials - think the mechanic seeds from Lem's "Eden". There would really have to be just one tree for creation - the Mother tree if you like. It would spread its roots across the procedurally-generated asteroid and take materials out of it. But, it can't realistically consume it all by itself. So you can use your seeds to 'build' augmentations - adding strategy by defining what type of material you want the seeds to process. If the asteroid is rich in common metals, and has a low amount of crystals, you can add silicate-processing 'bushes' and perhaps shift the scale enough to start making lasers. The defence trees would remain, but would again be subject to the same principle - their weapons would be defined by the materials, possibly limiting their use for certain combinations of materials.
The biggest change would be with the seeds themselves. A cosmetic change would involve different basic designs according to the primary type of material processed - silica, metal, or ice. Another change would be that once the Mother Tree grows sufficiently large in any one spot, it can begin the slow process of creating large "Capital Class" seeds. Their design would be heavily dependant on the available materials, and they would have arrays of weapons corresponding to them in quantity and power. Would make the game much more strategic, methinks.
I wonder what'll happen if I post this on their forum?