I had an idea for lighter and heavier (pickable, unpickable) objects immediatelly after implementing the grabbing, as why would you implement a game mechanic without inventing uses for it? So here the heavy boxes are introduced.

They’re like the earlier boxes, only they can’t be picked up or pushed. Instead, they have to be swung with a lighter box to move them around.

This build starts with the same old first puzzle, but as I needed the heavy boxes to be an obstacle in the second puzzle, I had to limit the amount of light boxes. What would prevent players from carrying lighter boxes from the previous puzzle, passing the point of heavy boxes completely? A one-way airlock for boxes.

I’m unashamedly proud of this little corridor where you can’t get boxes through the other way, but you can still get the yellow key back.

To the next build