Remarkable: Good use of sound effects.
Needs Improvement: Feedback! First, hard to tell which box is which. Second, because the text reads "RedCube1", it took me a while to realize that the "1" is supposed to be a quantity (without a space, I thought it was talking about a specific box). Finally, it's hard to tell when you're allowed to pick something up. Since you're using a RayCast to indicate "pickuppability", I would add some kind of highlight to the box that is pickuppable at any time.
Successful: The feeling of monotony, which hopefully was the point! (but also the sound effects made it more satisfying than it probably deserves to be ;) )
General: I worry that it would take away from the sort of casual feel, but maybe you could have a timed mode. This game seems like a good fit for a competitive experience.