When you are on the title screen if tilt left and right fast enough then the wording will change and it will say something different.
Feeling nosy
On the title screen, if you wait long enough, little Wario noses will scuttle onto the screen. Rotating the GBA makes them scurry off the screen.
Mawaru Made in Wario Mini-Game
Get a high score on every microgame through "Zukan" mode.
Unlock 9-Volt's and 18-Volt's Games
Beat Orbulon's stage.
Unlock Alien Item
Complete Wario's Final Stage.
Unlock Dr. Crygor's Games
Beat Dribble's and Spitz's stage.
Unlock Dribble's and Spitz's Games
Beat Jimmy's Folk's remix.
Unlock Easy Tower
Complete Warioman.
Unlock Hard Tower
Get 25 points on Easy Tower.
Unlock Jimmy's Folk's Remix
Beat Kat's and Ana's stage.
Unlock Jimmy's Games
Beat Mona's stage.
Unlock Kat's and Ana's Games
Beat Jimmy's stage.
Unlock Mansion Remix
Get at least 25 points on Tower.
Unlock Mona's Games
Beat Wario's stage.
Unlock Orbulon's Games
Beat WarioWatch remix.
Unlock Pyoro R
Complete every single microgame at least once.
Unlock Random Item
Complete a character's stage.
Unlock Skyscraper Remix
Beat Warioman's Games.
Unlock Speedier Spin Remix
Get at least 50 points on WarioWatch.
Unlock Thrilling Tower
Get 25 points on Hard Tower.
Unlock Tower Remix
Get at least 25 points on Skyscraper.
Unlock Warioman's Games
Beat 9-Volt's and 18-Volt's stage.
Unlock WarioWare Twisted
When you complete every game in the spindex, you unlock WarioWare Twisted in the games section of souveniers. The game restarts to the GBA load screen, but the load screen looks different.
Unlock WarioWatch Remix
Beat Dr. Crygor's stage.
Wario Bike
On the souvenir game Wario Bike, at the very end of the level on the last ramp, just keep turning it left.