How is it that every time I deliver something I ALWAYS immediately fall over backwards??
Once I figured out exactly what I was supposed to be doing and how to do it it was good fun, and a great concept for the game jam. The controls generally felt perfect, especially for the theme, the only complaint I have is the acceleration feels a little unresponsive which makes turning around in the aisles a little too difficult.
As for improving the game, since you said you want to keep working on it, the most important thing is a tutorial, since it was hard to figure out how everything works at first. The second thing would be some sort of obstacle that's a little more impactful than the oil spills, which were funny the single time I slipped on one. I get that they're probably not intended to get too much in the way of the already difficult gameplay, but I think something a little more would feel more fun.