Al brought this up in the PC demo's thread but this game deserves more. I ask myself, what will be the '06 Game of the Year? I'm torn between Oblivion and Armadillo Run. One took dozens of people half a decade to produce. The other took one guy nine months. The similiar fun factor is telling.
The goal is always to get the Armadillo, essentially a basketball, into the blue teleportation for about five straight seconds, under budget. To get it there you have many materials at your disposal: metal and rubber plates, metal rods, cloth, rockets, rope and elastic bands. Each level presents obstacles made of the same materials, gravity, and distance. Some levels have a likely solution meant to be used, but the beauty of this game is the infinite possible solutions that are just as valid. For instance:
I have no idea how to get the Armadillo up to the path with enough momentum to ride the spiral. Some type of pully system? A cantilever? Perhaps a slingshot and rebound contraption? Very likely all of those mechanisms could be created to successfully send the ball up the ramp. Instead I went for a more violent design.
The budget is merely a goal to progress to the next level so you can build way over the budget, you just won't progress. Seemingly impossible obstacles can be overcome with enough money. Once you've spared no expense then you can trim the fat here and there to bring it back down to Earth. Rope instead of metal here, extra support removed there, etc. The end result may fall apart in the process, but if it gets the job done first, right?
For $20 you get 11 tutorial levels, 50 normal levels, 10 bonus levels unlocked for every thousand dollars underbudget. You can edit new levels from scratch and share them with other players on the main site, with filesized in the kilobytes. Already there's a high quality sets that put the total over 100.
Gamasutra has an Indie Postmortem up.
Eurogamer has a challenge running where every two days a new level is released and players submit their solutions, cheapest design wins.
You owe it to yourself and every gaming writer that ever penned an article about how Indie Game Developers are a lost cause to try the demo.