Unicum

Unicum is an Arkanoid clone for Atari 8-bit that first appeared in happy-Computer magazine. It is notable for having fast and complete gameplay for a type in program, and also featuring 2-player simultaneous play (both players get half the screen to guard with their paddle).

The most popular version circulated has a set of extra levels first published in Top Magazin. Just press SHIFT+L followed by SHIFT+1 at the title screen and RETURN at the prompt.