I am curious if it is a single big level or what. It kinda seems like a playground where you are basically playing a Mario Godzilla game. Mario goes around doing little chores to earn "stars" or whatever currency you got...and a timer goes off and evil Bowser comes and you have to fend him off and then go back to work.
It also seems there may be places you can only reach during a bowser attack which is also pretty intense. Something tells me it will be a short bonus game but it looks fun.