I recently dug out my copy of WarioWare Twisted (along with my GameBoy Micro), which I probably haven't played for five years. Holy crap, that game is absolutely packed with content. Not only are there over 200 microgames (223 according to Giant Bomb), but then there are 140 unlockables.
These include toys, figurines, instruments, and even soundtrack records (which you can "scratch" by twisting the GameBoy). Just a huge amount of content to unlock, and unlike most game unlockables, these were actually super fun and interesting.
The only problem with this game is that, over the years, the gyroscopic sensor in the cartridge becomes less and less accurate. I have three physical copies of Twisted, and all three of the gyros have gone bad. After a few minutes of play, they'll get "stuck" twisting in one direction. It's a huge bummer.
Today, I found out that an Android emulator (called My Boy) actually supports gyro motion for this game, so you can successfully emulate Twisted on any Android device with a gyroscope. The real cart also has a rumble pack built in, which (I think) can be emulated, but my Nexus 7 and Nvidia Shield don't have rumble, so I'm not sure if that actually works.
But man, I started playing this game from the beginning, and it's just so incredible. They really don't make games like this anymore, and that's a huge shame. All of the WarioWare (and stuff like Game & Wario) have fallen way short in terms of both content and gameplay, compared to Twisted. This game is an absolute mini-game masterpiece.
Bust out your GBA.