I was able to get 47 without using upgrades.
I think this concept is very fitting in its similarity to snake. It's simple, fun, and has a deceptively tedious and not fun optimal strategy. It's probably a bit better than snake in that at least there's a bit of extra challenge in getting the last spot of a row.
Also, I think the dust particles would work better if they checked for boxes in the way and went up in that case (so the dust would look like it's from sliding against the neighboring box).