I was initially drawn to the anime by the cover.
I'm so glad I was sucked into the world of Btooom! and its awesomeness!
I devoured this anime in a single day!
Yes, I too can see some similarities of the plot to other stories (Battle Royale, Hunger Games, .Hack/, Condemned) With that being said what can you watch or read these days that you can't find something comparatively similar somewhere ...