Wario Land II was the last first-party title made for the Game Boy, and was later re-released for the Game Boy Color to take advantage of the new hardware. Wario's nemesis, Captain Syrup, and her Black Sugar Gang (formerly the Brown Sugar Pirates) invade his castle and steal his precious treasure. Outraged, Wario races across the land to defeat Captain Syrup and take back the treasure.
This run beats the game with 100% completion: collecting all treasures, completing the picture panel and completing the extra time attack stage (the Really Final Chapter).
We recommend reading the author's submission text; it has a great deal of information.
To see a run that aims for fastest time, check out the any% run.