What is an online casino playing guide? An online casino playing guide is a comprehensive resource of information about a specific game. Among other things, a guide provides information on the volatility of a game, the bankroll requirements, and the casino bonuses that come with each game. The internet has made casino slots one of the most popular forms of gambling, so casino guides are extremely useful and informative. Similarly, casino guides are also useful for new players and those who are just starting out in the online gambling world.