My biggest problem at the time of the film's release was, and is: it's called THE GAME. Knowing how studios market, no one was going to call it that and have it end with killing Michael Douglas (as another comment mentions, it was further hindered by a ridiculous amount of things that shatter the suspension of disbelief).
All that said, still a GORGEOUS film and -- like all Fincher work -- a masterclass on cinema as a visual art. I just don't think the "twist" element of it was ever that great.
"Parallel development" doesn't just happen with screenplays. What seems the best approach is in the aether and good storytellers will often come upon the same - even if untravelled - road. Like I tell young writers: no, it doesn't mean XX "stole" your idea -- it means your idea is a good one because it's in the creative aether calling out to you both. Good video piece (his, too).