Where are the pesky humans? Funny story, that. They blew themselves up. Now steam-powered robots have taken over the world in Steamworld Dig, while what's left of the "degenerate race of drunken, dynamite-wielding troglodytes" hide in caves beneath the surface.
Steamworld Dig is a 3DS hardcore platform mining adventure game. You play as a "steambot" called Rusty who, unsurprisingly, wakes up an "ancient evil". You deal with that evil by digging tunnels and collecting rare minerals, as one does in those situations.
The game drops later this year sometime -- no official date yet. For now, have some pretty screenshots.