OK, here’s my half-finished game. The idea was to make a full-featured block-based Tower editor to create a series of levels. Of course, I ran out of time and only included a few simple levels with one basic win mechanic – just stack the blocks high enough and let them come to rest, and you win. However, the editor is pretty full-featured and fun to just play around with, and it does a good job of showing off the underlying 2D Java physics engine.
Right click to drag around objects. Left click to create objects in the editor mode.
It’s a signed applet (due to the XML reader/writer I’m using for saving/loading levels), so you’ll have to click through a security permission to play. But hopefully it should be cross-platform enough so that you’ll be able to try it out. Have fun!