I played Gruntz many years ago. My name is Mihai Sebastian Petre, and I have loved that game. I use A Fighter as a callsign, but it occured to me many years ago that I visited the forum on the occasion that a free copy of the game was being offered as a gift to the 25.000th thousand visitor. But... I'm sorry.
I was that visitor. I was just a guest and then I suddenly left. Too quick, now can you please give me the game? I was just a few years old.
Writing with love from my hometown of Bucharest, Romania, Mihai Sebastian Petre
I'm afraid you are 13 years late and GooRoo might not even own this copy of the game anymore (also it's a german version). You'll be better off downloading it for free from one of the abandonware sites, as the developers no longer care about it, if you really want to play it. This forum has solutions to problems you may face while trying to launch it under newer Operating Systems.