Mine down to collect various ores and sell them to upgrade your machine speed, fuel tank or storage capacity. Find treasures an earn achievements. However, pay attention that you don't have unlimited fuel so you might want to get back to surface sometimes to recharge it. Also you can build awesome stuff to visually upgrade your house and increase it's level. For each level raised you unlock new upgrades for the drill.
A powerful app that creates tiles for apps or websites! You can customize the tile title, background color, style and even make them transparent to match your start menu style. You can also add blank tiles to fill in blank spaces.