I get a vibe of sorts for the ending right now - movie all about creativity, and by the end the protagonist(-s?) has saved existence itself from being snuffed out (think Who Framed Roger Rabbit, or The Neverending Journey), but at the cost of everything they have built; Their world lies either in ruin or is obliterated, much as a result of themselves using parts of it in clever ways to thwart pursuing assailants.
So, they quietly just begins to build anew, while the camera dollies away; New ideas, new efforts, retained enthusiasm, no crying over spilt milk.