Largely ditto SF but let me add a couple of thoughts.
A game normally has set rules and defined boundaries.
On the one hand, this means that if, say, you lose thousands of dollars in a board game, it's not real money, it's just play money, so it doesn't really matter. People will sometimes say, "Hey, this isn't a game!", meaning that, you are acting as if the consequences of actions were only for play, like in a board game. For example, if you made a business decision that was very risky and could result in many people losing their jobs, someone might say, "This isn't a game", meaning that you are not taking the consequences seriously enough. In that case, saying that you are treating something as a game is usually negative. In some cases, though, people will talk about a person considered the consequences TO HIMSELF lightly, and in that case they may say that he acted like something was a game and mean that positively.
When someone talks about "the game of success" or "the game of politics", what they usually mean is treating these things as a game in the sense of figuring out exactly what the rules are and how to win. That would be essentially a positive statement: we are going to discuss how to succeed at this endeavor. But note that the very same words could be meant in the sense I discussed in the previous paragraph. You have to look at the context to see which is meant.
And just a by-the-way, it could be argued that the metaphor doesn't really make sense. Many games do have serious consequences. You could lose all your money in high stakes poker, and you could be seriously injured in football, even though those are "just games". And in general there's an awful lot of money in professional sports. But whatever.