It's a real game as far as I can tell. It was originally created for the Game Boy Advance but since then, the publisher Orbital decided to make a version for the DS. IGN has reported on this awhile ago. Nintendo Power has both versions on their GameWatch forecast and there have even been two page adds for the game. I guess it's the long way of saying: it exists.
Personally, I've been waiting for information about the game because I've been kind of curious about it. But, there never seems to be any news about it, and I can hardly find any screens for it. Of course, I haven't searched for any for a long time because I'm not that interested in it. I just think it might have potential.
When I learned about the game, I thought it was a rip-off of Metroid as well. But the description I read made it seem a bit different compared to the description you just quoted. Maybe I'll look for the other description later but not right now.