This may be slightly off-topic, but in my opinion life's definately no game. And "whatsup", you give the best points against your theory:A game is something that only has minor consequences in the real life: when something goes wrong, you just reload or re-roll your dice. Even if you don't "cheat", a game is over in -whatever- two hours or so. Life lasts, well, your whole life. You can't rewind your life, a failed exam is failed and if your brother is murdered he stays dead, though the murderer is executioned. Maybe I could agree with you if you looked at a human's life on a larger scale, i.e. compared to the earth's lifecycle or so. From this point of view life indeed is as short and as irrelevant as a game. But for human beings tend to be quite self-centered, this point of view is quite far off to most.
Of course there are some similarities between life and games and some games may be very realistic (Sim City...), but those games always lack the seriousness of life: We all had fun flooding our beloved Sim-Cities and then reloaded, but look in the TV - we all know the pictures of natural disasters. Can this be compared in a serious way?
My encyclopedia describes a game as "something that you do for the enjoyment of itself". And though I must admit that life holds quite a few pleasurable moments, no one can deny that there are times that aren't nice, even make people take desparate measures. Only masochistic people would play such a game!
I think the attitude "life's a game" - while common and en vogue - is quite a dangerous one, because it makes people live their lifes in a carefree way. To me this means yielding to all temptations (and yes, I know the Oscar Wilde-quote), which is a bad thing, for it makes us unaware of the longterm consequences for ourselves (the girlfriend's annoying - dumb her, smoking causes cancer?), the society and future generations or the environment. I'm not a saint and plead guilty for some of the mentioned "crimes", but usually I'm definitaley not happy with this.
"Whatsup", I don't want to flame you, attack you personally or whatever, just state my disagreement. 
And oh, excuse my clumsy english - it's been a long time that I had to write essays like this in school 