Cassette 3: Attacke © 1975 Interton Electronic.
It plays a very similar version of one of the oldest video games ever made: Ralph Baer's Chase Game. The game consists of two squares (players) chasing each other. In Ralph Baer's version, both players had the same size, and one would disappear uppon colision with the other. Here, the players have different sizes to avoid confusion while playing, and a beep is produced when one thouches the other.
The circuit board of this cassette is the simplest of all: it contains just a few resistors to enable the two players and set their sizes, and one 4011 CMOS chip which acts as a collision detector (Player 1 AND Player 2 = Collision). A capacitor filters parasites from the power supply.