Talking about "figures" this way generally means numbers in the range with the given number of digits, or figures, before the decimal point, especially when money is involved. So someone with a "six-figure income" in America makes at least a hundred thousand dollars ($100,000 has six digits), but less than a million ($1,000,000 has seven digits). Since they're talking about success, and specifically financial success, we can tell that they mean the games make somewhere between 10,000 and 1,000,000 each, probably roughly in the middle around 100,000.
It's much less common to use this pattern when not talking about money, but saying it had "seven figures of downloads" would usually still be understood.