how many stars needed to beat game?

[Felcher]

is it like super mario 64 where for example you can finish it with 70 stars out of 120? or do you need alll the stars?

[a]

Assuming you're talking about Adventure mode, you need 77 stars to open the last boss in easy difficulty, and 89 stars in normal difficulty. For Speedrun mode, you need 26 stars in easy diffulcty and 30 stars in normal difficulty.

[Felcher]

how do you change difficulty?

[a]

Difficulty is selected when you start a new game.