How to Know When a Game Is Done

I ask that myself all the time especially with this game. How do you know when it's time to kind of stop and ship something? I was planning to do this whole thing around an evolution mechanic where you get to like upgrade your your guy as you go along. It still sold way more copies than I could have ever expected for a little dinky like one dollar game. There are people who are just like oh man I wish this had online multiplayer like a gario or something like that but it's just like um I don't know that folks still liked it.