Fair play notice

How to read these notes, and their limits.

Please read this before relying on anything in these notes.

Opinion, not instruction

These are general design notes. Rules for in-game purchases, odds disclosure and age ratings differ by country and change over time; publishers should check current local requirements with qualified advisers.

Games of chance

Some pages compare game design with lotteries or casino games, to explain probability. Those comparisons are not recommendations. Gambling is restricted by law and age everywhere, and money spent on it should be treated as the cost of entertainment.

Links

Outside links illustrate a point and are not endorsements. Some lead to pages in other languages and from unrelated industries.

Contact

There is no support desk here. Corrections are applied when pages are revised; each page shows its revision date.

Saved 2026-10-22