Super Mario 64: Openworld Guest

SM64 Openworld Quest is a ROM hack made by TheGael95. It was released around 2016, and contains 70 Stars. This hack modifies most of the vainilla levels to match an openworld environment. In addition to that, it includes a few custom levels.

Plot
Princess Toadstool sends Mario to come to her castle to save from Bowser. When Mario arrives, he meets the Lakitu Bros., whom are filming Luigi. They go inside the castle and hear a familiar voice telling him to get out of the castle. Toad informs him that Bowser and his henchmen invaded the castle and has kidnapped the princess and is holding everyone hostage inside the castle walls. He has also stolen the Power Stars and given them to his minions who are hiding in paintings spread all over the castle. Mario hops in the magical paintings and retrieves the Power Stars in order to defeat Bowser and save the Princess.

During the journey, Mario makes his way to more areas of the castle. When he finds out he has enough stars, he goes into Bowser's final level. Once he makes his way through the long course, Mario sees Bowser, and the two battle. When Mario defeats Bowser, he gives up and hands him a Giant Power Star, before he disappears. Mario grabs the star, and has been given the Wing Cap and flies away back to the castle.

As Mario's Wing Cap disappears, he uses the Giant Power Star to make Princess Peach appear. Peach wakes up and thanks Mario, by giving him a kiss, and the cake she had promised before.