This is the best game and I'm obsessed with it. It took me hours to finally beat it, despite knowing what to do (throwing the boxes in their respective sections before starting to put something on a shelf). Rather than starting in the cleaning aisle like other people, I think it's best to start in the Halloween/DIY section. You need quick movements to be good at this game. Don't waste any time, and don't spend too long in the staff rooms.
Notable glitches: If you press the wrong button while stocking something on a shelf, the box will fall in a lagging way, then when you pick it up and try to grab items from it, they won't appear. You have to restart the game. Sometimes when someone approaches me, the game will randomly glitch out and I'll be walking on the ceiling for a moment. There is of course the notorious glitch in which someone will try to tell you what they want but no text will appear.