Dig through ALL the rock to find the hidden staircases in the houses, there are a couple people you need to talk to, then you go to the graveyard and check all the graves to free the people's spirits.
The platforming sections aren't actual platforming, the game just switches to a side view instead of overhead, but all the the controls are exactly the same. It does make for a really nice bit of variety though, especially since those sections usually have some of the best graphics and coolest effects in the game.