Tetrolled: Tetris but it trolls you

Tetrolled is Tetris but with an additional layer of hostility: as time passes, obsctructions pop into existence at random spots on the board. Trasevol_Dog made it in just 2 hours for the Ludum Dare game-making contest. The source code offers a nice simple example showing how the Pico-8 "fantasy console" is coded.