Very innovative concept in which jigsaw pieces serve as a defense for attacking enemies.
Unfortunately it happened very often that i placed pieces and enemies swam along where i did not place any pieces. It's very frustrating when you have built entirely wrong and can no longer place any parts in a gap. You just wait for your slow death at this point. Therefore i would liked it if the pieces can be repositioned again and rotated. That would provide a greater depth of strategic gameplay.
Overall i think this is a pretty decent submission. I always like some strategy games in jams. Good job.