Puzzle game. Each container is a grid of varying shape/size, and you have to put all the items (also of varying shapes/sizes) into them. You also have weight limits for each container, so you’ll sometimes have to decide between increasing an object’s size to reduce its weight or making it heavier so it’ll be smaller. Also, most levels have space left over once you’ve gotten everything in, so you can add extra candies into them to get more points (larger candies are worth more points), and getting enough points is how you get three stars (the game never tells you the target score, but the star fills up as more candies are added, and it becomes brighter once you’ve reached the threshold).

The difficulty curve is inconsistent. One level will be tricky to get all three stars, and the next you’ll get them all really quickly, almost by accident. The game also has a whole two levels where you’re not supposed to put specific items in the same container before the game gives up on that gimmick, but since it’s free, I can recommend it for the tricky puzzles it does have. You can play it here: https://legoliomanikas.itch.io/scale-mail

P.S. I did notice that it has an expanded version on Steam, but between the issues with the free version and the fact that the store page says there are only nine more levels in the paid version, I don’t think it’s for me.