Crystal Shard In The Bullseye
On Ripple Star, go to the level before the "Miracle Matter". In the room with the orange and red floor pattern, beat the people inside that room. After you do so, use the burn + spike combo. Shoot for the center of the floor pattern. If you hit it, you would find a hole there. Jump into the hole, and you will get a crystal shard.

Crystal Shard In The Buttons
On Shiver Star, go to the third level, and when you get to the room with the colored buttons, push down on these buttons : pink, red, and blue. If you do it in that order, a crystal shard will appear.I hope you get one

Sound test
Successfully complete the game to unlock a sound test selection on the options screen.

Bonus modes
Collect all crystals in the game (it will say 100% on your file at the file selection screen) to unlock Boss Battle (Bosubuchi) and Movie Viewer (Zenbu Miseru) modes.

Infinite lives
To get an extra life, get the star at the beginning. Press Start and select "Try Again". Go to the same level and go back to get the star again. Repeat this as many times as needed to collect an unlimited amount of lives.

Extra Star Piece or Treat
Return to the beginning of most levels to find a Star Piece or Treat. Moves (combos) Fire: Fire ball
Fire + Stone: Rock shooter
Fire + Ice: Ice and fire blower
Fire + Needle: Bow and arrow with fire arrow
Fire + Bomb: Fireworks
Fire + Spark: Solar powered fire
Fire + Cutter: Fire sword
Fire + Fire: Fire bird
Stone: Rock
Stone + Ice: Skating soap
Stone + Needle: Drill
Stone + Bomb: Dynamite
Stone + Spark: Electric rope tied to stone
Stone + Cutter: Stone cutter
Stone + Stone: Big rock
Ice: Ice blower
Ice + Needle: Snow flake
Ice + Bomb: Snowman bomb
Ice + Spark: Refrigerator (food gives you health)
Ice + Cutter: Skate
Ice + Ice: Snowball
Bomb: Bomb
Needle + Bomb: Spikey bomb
Needle + Spark: Thunderbolt
Needle + Cutter: Bite (commercial)
Needle + Needle: Spikey gadgets
Needle: Spike ball
Bomb + Spark: Light bulb
Bomb + Cutter: Bomb that hooks onto opponent
Bomb + Bomb: Missile launcher
Spark: Electric shock
Spark + Cutter: Electrical double bladed sword
Spark + Spark: Electric ball
Cutter: Boomerang
Cutter + Cutter: Boomerang with blades

Break through walls
There are various walls that must be broken by specific abilities. The ability depends on the color of the wall: Light Brown: Spike
Brown: Rock
Red: Fire
Green: Cutter
Black: Bomb
Blue: Ice