Thank you for the detailed feedback!
Originally, I was planning to have upgrade paths for everything in the store, but didn't have time to finish. The charging port is not supposed to be that expensive, but I didn't get around to that either. I also wanted to be able to expand the hamster's area in future "levels" but alas.
Good idea about limiting the amount of seeds per bowl! Adding more bowls means hamsters may not have to travel as far to find food, but that might not make too much difference since the area is pretty small.