Regulated markets work dilligently to steer the casino industry towards ensuring minimal exposure of gambling-related content to minors. This includes demo play (even though it's free to do). Although you will find video content here on CasinoGrounds, you will not find any playable demos.
Free slots behave exactly the same as oneanother, with the only difference being that you can't lose, as you're not placing a wager. It is, however, the casinos job to ensure that a registered player is who he/she says he/she is, and that the player is of legal age.
Regulated casinos are also required by law to offer all registered patrons tools for responsible gambling, allowing you to set limits to how long you can play, and even exclude yourself temporarily, or permanently.