The Great Giana Sisters is a 2D platformer inspired to Super Mario Bros (you might say "clone"). It was developed by Time Warp initially for the Commodore 64/128, in 1987, then ported to Amiga and Atari ST in 1988.
The development team took the task of copying Super Mario Bros very seriously. They tested and played the original game for several months, trying to reproduce it. Unfortunately, all this effort didn't end well, because Nintendo blocked the sales of the game almost immediately, threatening legal action for copyright infringement.
Probably the Great Giana Sisters would not be so popular if Nintendo didn't block it. In terms of quality, it's not the best platformer you can find for Amiga (not like Superfrog, for example). Anyway, it's a nice title that you try, if not for the game, for the excellent soundtrack composed by Chris Hülsbeck.