I really like the concept! I love sorting things, and games that use that concept. I also was struggling to decide what to keep for granny and what to donate, heh. But that's the point, so very well done on that part :)
On the gameplay: I wish the timer was longer. In my second round since I new more about the items from the first, I was still racing to donate and throw away as much as possible so that granny can move. I also noticed when I was trying to donate the knit magazines (I would donate them since people love knitting) the character was colliding with them and they basically flew out of the donation box. So I don't know if they have to be kept or trashed, or if that was a bug.
I had fun, very well done guys :)