I really really liked the concept (I love puzzle games), and having the track visible is super nice, I've never done pathfinding, seems hard!
Sadly, the game is just too fast. I understand it being time sensitive is a core mechanic, but it's just unforgiving. If it let me replay the same level over and over it wouldn't be such a problem, but as it restarts form the beginning, it gets frustrating. I got to the level where it's just empty and there's a button but i didn't know how to push it, and the mouse is just to fast for me to redirect it so early. After a while I started having issues with the box placement, sometimes it worked as drag&drop, sometimes I had to click on it and click again to place it, and that lost me some games.
I don't want to discourage you, you probably didn't have any feedback until now so it's normal you tuned the speed for yourself. The foundation is solid and I encourage you to keep building on it if you also like the concept.