Hoshi Saga 2
From TIGSource description: "In Hoshi Saga 2, you are presented with a series of mini-games and the object of each is to find a hidden star. How the star is hidden and how you find it varies with each game. It’s kind of Wario Ware-ish in that the fun comes from figuring out what you’re supposed to be doing (minus the time pressure).
The levels are presented in a grid, and at the end of each row and column is a hidden mini-game that can only be accessed once every other game in the row/column is beaten. Beating all the hidden games unlocks the credits.
The games are all very clever, and beautifully presented. Quite lovely!"
There's a complete walkthrough for the game compiled from JayIsGame comments here.
Also, there's another walkthrough in the 28th comment on this post in freegamesnews.com here.
There's also a video walkthrough for the game on YouTube by bewnt with captions explaining what to do in each level: