This is a very well-made and beautiful game! The art is very cute, the colour is pleasing to look at, the music is fitting, and the characters are adorable, I like this very much! The gameplay loop is simple and fun. Strangely the game is surprisingly calm and I don't know if it's a good thing or a bad thing, but I do enjoy that regardless.
As a suggestion, I think the game suffers a bit by making the player walk the same path a lot, and it would be nice if there was a second elevator on the other side of the building. It should really ease the boredom of going the same path twice every time you are going somewhere, and would encourage some tactical thinking too! I would also suggest allowing the player to carry 2-3 items at once, and this should have the same effect on the game as above. It's also an excuse to make stuff spawn more quickly and make the game more chaotic too!