Acid Drop was a puzzle game released in the early '90s. It was Dennis Kiss' take on Sega's Columns, a puzzle game that required you to stack (you guessed it) columns in vertical or diagonal sections. Acid Drop strips the latter and only requires you to stack vertically. The game has a total of 30 difficulty levels, and all the while, you get to put together the puzzles to the relaxing tunes of Beethoven's Fur Elise. The main pressure comes from the falling blocks reaching the top of the screen, ala Tetris. Acid Drop is notable for being the last game released on the Atari 2600, as console production ceased after this.