I like the demo. I also like very much that you try to keep the features down to a minimum as you write:

I tried a few other tools over the years, but the number of features they offer often distracted me from using it efficiently, making time tracking an effort on its own.

While tsr may not have an extensive list of features, it has proven to be effective for my needs, and I believe it may also benefit others in similar situations.

In that vein I wouldn't add any new features and seriously consider removing tsn.