I checked the app and the website. The app was produced by Daniel Suarez. He has a portfolio website mystiquetechnologies.com showcasing him as a full-stack iOS developer. He is developing another app called Entropic Pursuits for setting (and hopefully achieving) goals.

About the product, I like its concept being simple and minimalistic. Both concepts gear products towards focus. I'm also glad to hear that you use this app yourself - that's one of the most effective marketing strategies I know - promoting and advocating something you use yourself.

I also use something something similar on my Android phone. It's free and offers in-app purchases. One possible downside is that the product is only available for iOS.

I wonder if it has a synchronization feature.