We built this game as a part-time project, to prove that it's not too hard for indie developers to make money on the Android Market.<p>Investment:<p>- 100$ design (template)<p>- about 200 hours of work for us, two developers<p>Since this is HN, some technical details:<p>Because of limitations on google's push notifications (C2DM), we rolled our own solution, with an xmpp server helping on that side. Every other web-service is built with plain PHP, residing on a different linode vps.