Rampart

Rampart is a 1990 strategy video game developed and published by Atari Games for North American and European arcades, with distribution in Japan handled by Namco. Presented from a top-down perspective, the game tasks the player with defending their territory from enemy invaders. The gameplay alternates between a building phase, where the player constructs walls around vulnerable castles, and a combat phase, in which cannons are used in an attempt to drive back hostile forces. A trackball is used to control the game. It had a limited US release in October 1990, followed by a wide release in February 1991. Rampart is a precursor to the tower defense genre, popularized in the 2000s.