The Great Giana Sisters was a legitimate game though—while the gameplay was obviously almost identical to Super Mario Bros, code wise it was technically very ad

The Great Giana Sisters was a legitimate game though—while the gameplay was obviously almost identical to Super Mario Bros, code wise it was technically very advanced as far as C64 games went. The way you phrased it seems like it was a bootleg version of the NES game. But Nintendo was just as litigious back then, so the game didn't last long.