This is really damn good. The premise itself is excellent, and your execution of that premise is absolutely wonderful as well. I love this so much. I would never have thought of this for the theme of the jam, and yet it fits so well.
The only criticisms I have are nitpicks about the building system, which I'm sure you would've fixed if you had more time. I'll list them anyway just for completeness sake:
- I wish the hitboxes for cutting the nibs were a little bit larger
- I wish that cutting the nibs on a certain part would release just that part without having to cut all the nibs on the whole sheet
- I wish that it was easier to grab an assembled part without disassembling it (like grabbing the torso to move the whole thing. Maybe you'd need to right-click if you wanted to disconnect those?)
- I encountered a bug once where a cover piece connected to multiple anchors at once
Once again, those are just nitpicks. They're things that it took me a moment to figure out when I first started playing, but quickly faded into the background. Wonderful work.