Okay, so CPD was released two or three days ago. For those who haven't played the prototype, it's an interesting sandbox game (although ARE objectives). The game is played pretty much entirely with a mouse. Draw a line, it becomes a solid line. Draw a box, it becomes a box. Everything you draw has physical properties. If you get further in the game, you can draw hinges and ropes. Rockets are also introduced. There's also an awesome level editor (which also allows uploading your levels). It's pretty fun.
I bought it today, and although short (In 2-3 hours I finished like 2/3 of it), it's really fun. The level editor will give it near-infinite replay value, though.
http://www.crayonphysics.comFull game is $20, a demo with two of the islands is available.
