It definitely works. And I never tried putting the theory into practice until just now. So even though I said all that stuff before, I must say now that its not so easy to implement. At the moment I'm using two movable goals stacked on top of each other. They are being pushed up and down a shaft using man-cannons and gravity. I use two, because there is a gap of space in-between the goals in which the moving immovables aren't being scored. So there is one visible "frame" of the animation of the moving immovable. The problem is, the movement speed of the goals is both inconsistent and downright unfavorable. Which causes all kinds of issues with the animation. I would like help coming up with ideas to move movables in a consistent manor and a favorable speed. Or possibly other ways at approaching the animation process. I can't render a video. And screenshots won't do much on capturing the motion.
You should check out this and this. Using balls rolling down rails would give you much more consistent animation.
It might be possible to make that work. But I'll have to experiment with it. Problem with balls is that they rotate. I would need to make sure they rotate in one direction. So that the side of the goal shape that is hitting the immovable objects is consistent.
Well, as long as your goal is a fairly consistent shape - probably a cube or a cylinder with it's height set to about the same as it's diameter - it should be fairly consistent in deleting the objects. Another option would be to use crates and just let them freefall into a kill zone. Then you don't have grav lifts to deal with. Depends on whether you want vertical or horizontal motion, I guess. Edit: using rails to roll the balls down should give you a fairly consistent set-up. As long as the balls are only touching the two rails, they should only rotate on one axis.
Aesthetics. Awesome puzzle elements. Mario-esque gameplay with moving platforms and such. Also think its possible to remake the windmill thing from The Last Resort. There is definitely much more than that I'm sure.