The Great Giana Sisters is infamous for being the game that Nintendo went after*, because it copied the formula of their Mario games a little too closely for their liking.
In truth: The Great Giana Sisters IS very much a Mario clone. In further truth: it’s not a patch on any Mario game that I’ve ever played (and I’ve played most of them). No. The Great Giana Sisters, with some perspective, is – at best – a reasonable clone of the Mario Bros. games. It has a slightly slow and sluggish feel of its own that differentiates it from Nintendo‘s games, although it does borrow pretty much everything else from Mario, including the end level bosses.
Before it was withdrawn, The Great Giana Sisters enjoyed some success on a number of different platforms in and around 1987 when it was originally released. The Commodore 64 version is probably the most well known, although there are official 16-bit versions too.
Since the game was withdrawn The Great Giana Sisters has enjoyed some success on the hacking scene as well. Not only have many fan-made versions of the game appeared for the Commodore 64 (some of them brilliant), but the game has also been unofficially ported to a number of other different systems too, such as PC MS-DOS, Dreamcast, Nintendo DS, Linux and Mac.
* = It’s become an urban myth that Nintendo “opened a lawsuit” against developer Time Warp Productions and publisher Rainbow Arts, to stop sales of The Great Giana Sisters, but that actually never happened. Since the first level of The Great Giana Sisters pretty much copied the first level of Super Mario Bros. down to the individual blocks, Nintendo persuaded Rainbow Arts that it was clear copyright infringement and the game should be withdrawn. So the dispute was settled way before any court action was necessary.