The colours are also different for each word - selected at random. In the emulator, this is CapsShift-3. Another well known item, which I originally saw on the TRS-80 and later converted. The instructions are included in the game and are fairly obvious. Space drops the ball.
Points are scored by dropping the ball on a number, ball is burst by dropping on a spike.
There is also a time limit to the game. Much of the scoring depends on luck, as the numbers can combine together when generated. It is also impossible to drop the ball between the spikes, so don't bother trying. As an interesting side effect, this program also helps the 'randomness' of the random number generator, which is also used to select words in the Hangman game. Playing this game should therefore give more random results in Hangman 123.