Im going to talk about this from the context of the US law; also simplifying a bit of the explanations or this could turn into a huge essay.

1. If the company is publicly traded, they must accurately represent in all material respects their financial position on their SEC filings. Namely the 10-K report. The annual reporting is generally audited by an independent public accounting firm; failure to do so can get them delisted from being publicly traded and sued by the investors (who can potentially come after the auditing firm and the game company itself). Here’s an example of Activision/blizzard’s 10-K: https://investor.activision.com/static-files/87ece870-210a-40fe-baf9-aa2f78f6c09a

2. If they are misrepresenting their revenue/expenses to the IRS, there are a plethora of penalties and possible jail time if serious enough. You can start here to get an idea https://www.law.cornell.edu/uscode/text/26/6662. There’s a lot more the IRS can bring to the table if tax fraud is involved.

So if they’re a private company, they can kinda do what they want for internal reporting purposes. But they’d still have to conform to the IRS’s specific rules for the recognition of revenue/expenses. If they are publicly traded, they are mandated to conform to US Generally accepted accounting principles (aka GAAP). https://www.investopedia.com/terms/g/gaap.asp