It would be interesting if one could differentiate between playable games, and in game purchases are "fun", versus games that are unplayable in the 'free' mode without purchasing additional tokens. Its the latter that people really hate.
It often depends on your skill level, whether you take breaks from the game, and how much of a completionist you are. In some games these factors interact in complicated ways.
From a regulatory perspective, I'm afraid the best we can do is:
* Ban tying game mechanics to time outside the game, whether it's "wait 8 hours unless you pay" or "this reward is only available for 4 hours" or an insidious combination of the two.
* Increase transparency, e.g. by asking app stores to show graphs of (time played) vs (money spent).
"The use of the word "free" (or similar) may be tolerated for games which are not entirely free, if it is complemented by appropriate qualifications characterising upfront in a clear manner what elements are for free and which ones can be purchased. In such cases, the consumer should be able to access discrete parts of the game that stand alone without the need to make purchases. "Free" may not be used where the consumer cannot, without making in-app purchases, access content integral to gameplay or play the game in a way that he/she would reasonably expect. "
Essentially, the customer must know what parts are free and which have to be paid for prior download. There is going to be grey zone of course, but if you app have paywall, it shall not be called free.
On the other hand, you can sell custom avatars or additional levels and call your app free, as long as the description says something like: playing first five levels of the game is for free, but custom avatars and additional content have to be paid for.
