Many games are marketing themselves as being free, but then they earn millions of dollars each year with in-game purchases. If the idea is to fight such a system, I would understand. It's either free or it's not. Don't tell me I can play a game for free if I can't do it normally because I have to separately purchase all kinds of things.
It depends on the game. The free games I've seen that have in-game purchases are really free and whatever you buy is just cosmetics that won't affect your game. Like DOTA2 from Valve.
In any case, the flaw actually exists in NFTs because you
have to buy the token otherwise you won't be able to play the game in first place! In other words "free game" is not defined in the NFT world.