Thank you so much for the feedback! Endless Mode was actually the original implementation of the game. By the time I almost had it working, I decided to have a "boss" character come in and give you instructions. Then I thought of a bunch of funny jokes, and the game shifted to the story mode. So at the end of the jam, I just had to do one or two small things to make Endless Mode viable. If I could go back in time, I would have only done story mode like you suggest and fleshed that out even further.
Obviously the first level is scripted so that the belt starts zooming by and you can't keep up, but after that the only penalty to missing too many dots is that you get the "bad" ending. Pre-loading dots on the belt randomly helps ensure the player actually finishes the level, but once I added the ability to take dots OFF the belt, that allowed the levels to essentially be endless and never progress. With more time, I would have safeguarded against that for sure. Great feedback! Thank you again!