It's very bare-bones. Got the most powerful upgrade in under five minutes. After that, there's nothing left to do. Try turning it into a proper game with more upgrades (fertilizer, grow speed, different levels, for example) and a prestige mechanism.
Nice game, but spores upgrades don't work and the balance is off. It takes around a minute to get 4/5 skill points. It takes about 10 minutes to get 7/8.