Your barrier in gaining popularity once you launch is going to be cross-platform support. It sounds like you started wholly with Android, with other platforms coming further down the pipeline. These days a product that does not have apps for at least Windows, Android, iOS, and OS X severely limits its customer base.
Android essentially represents only a subset of phones and tablets. An app like yours is useless to many people unless it has desktop equivalents, as mobile-only access heavily restricts a user's ability to be productive where and when they need it. I might be an edge case, but I use Windows, OS X, an iPhone, and an Android tablet. Your app could be the most functional and usable todo app out there, but a competing product with 10% of your features is going to wind up being my choice simply because I get to use it across all my workflows. Platform support beats out the quality of the app, every time.
Based on your screenshots, the app is wonderful. I simply suspect you have focused too much on launching a 100% complete product instead of starting with an MVP. Obsessing over having a perfect product that launches too late to market, while your competition launches early and takes your cake, is all too common a scenario.