Peach's Castle is a puzzle type game where goombas invade Peach's Castle. Mario uses shells to throw at goomba's, but there are too many. Mario finds three different statues of him with a key. The keys unlock doors to make the shells bigger, on fire, and frozen. You can also unlock minigames and explore Peach's Castle.
The Xtra Levels
After you beat all the goombas and stuff, you can unlock a new level called the Red Arrow Levels. Mario shoots a red arrow through Peach's castle and you must steer it around rooms and stuff. Each room shows different lighting, sound, and graphics to see. There are 20 different red arrow levels, and the goal is to reach the target with out getting hit by statues, doors,walls, torches, etc.
Types of Goombas
There are six types of goombas to battle:
Green Goomba (Medium)
Green Paragoomba (Hard)
Grand Goomba (Hard)
By the way, this was a cancelled game going to be released on Nintendo Gamecube, but it was never released.