After some tinkering and trial and error with the controls, I figured it out and realized this was an ok idle game to waste some time on. (You hold down left-click to put down spores, that took ten minutes to figure out lol)
I think I understand most of what the upgrades do:
Spreader: Auto-puts down spores.
Purifier: When the spore overflows, it increases the next spore amount you gather.
Enhancer: You gain more from each spore.
Gun?: Zaps the spider. Idk what the spider does, but I think he steals my spore that gets put down. (What's the spiders name?)
The last thing I don't get is why you can unlock upgrades you won't use until the distant future. (i.e. unlocking obirutob upgrades when you start the game).
However, in my opinion, the vagueness of each game adds its charm to each game-- but is still frustrating to figure out at first glance.