After playing with the demo, there is one thing that really jumps out to me I don't quite understand. It's looks like time get grouped into these little 'blocks' on the bar on the left. It's not immediately clear what forms a block though. Also, I don't quite understand the use case for being able to drag the blocks around? If you drag one, the start and stop times change for every task in the block? Weird.
This seems very fragile. What if I accidentally drag a block out of place, and don't remember the exact start time? Then I have effectively 'broken' my time logs for a whole block of work. To me it would make sense to have the blocks locked by default, and allow unlocking in the case you need to move a whole group. But I can't imagine ever needing to do this very often.
I will say, I really like the concept of the continuous scrolling main time bar on the left. Anyway, trying to offer constructive criticism, not trying to bash this project. Looks like the project is still young, and you've got a great start here! Keep it up!