The game doesn't really tell us all that much about the story or the gameplay, the Steam description is surprisingly short (and that's being kind).
About the game:
Adventure waits below the surface...
Grab your pickaxe and dig into the sequel to the award-winning SteamWorld Dig! A platform mining adventure forged in Metroidvania flames.
In search of her lost friend, a lone steambot and her unlikely companion must dig deep, gain riches and explore an underworld riddled with danger. But time is running short…
The developer has sent over a key, so hopefully I will have some thoughts up within a few days of release. It certainly looks good, although the first game didn't really hook me. The first game was well reviewed in general though, so hopefully they've taken all the good bits and made it even better,
What I can tell you right now, is that is probably 64bit only. Time to upgrade if you still haven't.