After Taito released its smash hit Arkanoid, the competition was quick to come up with similar games. Namco created the unremarkable Quester, while Sega came up with the more interesting Gigas.
Since it was never ported to other platforms (not even, as far as I could find out, one of Sega's own consoles), it has remained far less well known than Arkanoid, but is generally considered the better game.
In any case its graphics show more class, the title screen is a masterpiece. Still in the same year there was a Gigas Mark II with slightly different graphics and, it is to be assumed, different levels. There was also a "cheap" version of Gigas, or at least a very similar game, on 8-bit hardware under the name Riddle of Pythagoras.
Gigas was the obvious model, right down to the graphic border, for the 1988 Amiga/Atari ST game Giganoid, which, ironically, some reviewers dubbed the most blatant Arkanoid clone yet.