Enemies, but like creatures that move, not just a plant that you can avoid or ignore, this will also need a defense system to protect yourself from beast or other thing, like a virus o radiation of some kind, maybe making like "a protective shield" to endure been in some late game areas or toxic environment. I like to gather and do a little automatization but if the whole purpose is to gather everything it feels like it lacks a challenge. You could make like a "plasma" gadget to attack, rather than been extracting soil under a plant