It's a pity in a way that the game was released into a coding competition and not just into the community as a while.
I tried contacting them sometime ago with regards to my site in the sig which is retro based and had no contact. For myself, Great Giana Sisters was very retro in itself and there are plenty of people there who would love it.
Equally, this is a game that I remember well on the Atari ST and the Amiga. I even once owned an original for the Atari ST!
Fast forward to a few years ago. I do rememember a Quake mod based on Great Giana Sisters (I believe that it was even called this). To my knowledge nothing bad happened to the mod'ers there. Also the fact that this was not for profit.
That screen shot was one of the first things I had seen on the unheard of GP32 for me. It absolutely blew me away. I knew that it was not available, but it did not stop me from getting the great little console.
All this being said, I'd hate to see a coder get into legal battles over a release of this. However with hindsight, an unamned release would have been great.