Once you finish all the levels most of the fun is in finding other challenging solutions. A lot of the time the Victory dialog gets in the way when you want to watch the target (if you're working on a champion, or whatever). It would be nice to be able to turn it off, or make it much smaller in the corner.
It also would be nice to be able to save previously assembled parts, even if it were limited to just a few parts, so they can be quickly reused in multiple levels.