I've been thinking of remaking this for a while now but I finally got around to it. Here we have an offline continue game engine, which in this case allows you to grow your plant offline. Essentially you start growing your plant, save it if you need to leave and go do something else, and then paste the save code in when you get back and the plant will act as if it was growing while you had the tab closed. This engine is fully offline, no need for any unreliable cloud data!
I realized while making this the possibilities this concept has. You could make a system where players who haven't been on your game for a while get a "Welcome Back" bonus, or you could use lists to expand this engine and make a full-blown offline growing farm game! You could even use it to make a clicker heroes system, where the player gets coins based on the heroes that they have and how long they've been gone. I combined my secure save code generator and my offline continue game concept to make this, hopefully it helps someone! I'm very excited to see what projects could be made of it.