Had a great time, but here’s some criticisms, as per your request.
I got stuck in the tutorial for a while trying to figure out how to scoop up ice cream. If I’m not mistaken, you need to drag the mouse downwards, and then release left click, on the flavor you want. I feel like the tutorial could be a bit more clear.
Other than that, I think the game would benefit a lot from having a sound effect for each action (scooping up icecream, putting it in a cone/tray/sandwich, adding topping), and maybe some spooky ambience during the nightshift.
All in all, great job! Especially for your first shared project!