Chartbuster and chartbusting arose in the 1950s as a marketing/promotions term designating recordings which “broke” or “busted” onto the national “charts” of bestsellers, and it has since been extended to other commodities, mostly in entertainment: books, movies, games.
There was however a somewhat older parallel usage for sales: ‘chartbusting’ sales were those which increased so sharply that the line representing the value “busted through” the top of existing graph. My impression (and it is no more than that) is that this is closer to how chartbuster and chartbusting tend to be used outside the recording industry—for works which approach or break sales records. It’s not enough to make it onto the list of bestsellers—you have to be at or near the top of the list over a long period.
Some more general observations: Any word or phrase may be extended beyond its original scope to similar or analogous situations. Whether a particular novel use is “acceptable” depends only on its being accepted—used and understood—in discourse. Eventually the dictionaries will catch up.
So your best authority for contemporary usage is not a dictionary but a corpus of actual utterances. The most accessible such corpus for popular use is Google; sure enough, if you Google “chartbuster games” you will find† several such uses. Several of these are false hits on a game named “Chartbuster”, but there are others like this:
Below we have short-listed some of the chartbuster games of this year. They simply excel with their breath-taking visual effects and classy gameplay. They are being highly talked about not only among gamers worldwide but also among game critics. —blog.game4u.com, “The Game of the Year Contenders 2013”, posted 11/27/2013
A question which remains is whether the uses you find suggest suitability to the context and register in which you want to work. That is a judgment call.
† Or at least I found—Google reports different results in different places.