I got a second copy of this amongst a bunch of games today, and the cover has a couple of differences to my original.
The original looks like any other black-box Megadrive game, and has 8 languages on the back:
The second looks more like a Genesis game [but is definatly PAL].
There's a solid border around the front cover, and a bar-code on the spine rather than the back, and it's in only English on the back cover (there's no manual with mine, the pics are from eBay):
A quick check on eBay suggests that the original is much more common.
Does anyone know if the Genesis-like version was possibly a pack-in at some point? Or if there are any other games like this?
I know there's a few of packaging variations throughout Europe, mainly for games with translated in-game text (and some 3rd Party games), but it's the first time I've seen the Genesis-style box for a Megadrive game.