Why YSK- Even if you're already knowledgeable on these things, it never hurts to reinforce something that could save someone's life. Also since there's lots of little things to be mindful of when responding to an emergency, it can be easy to forget. I first went through the series a decade ago when it came out and after going through it again today I got a few things wrong. That's not to say it's a fault of this series. I feel like I retained a good amount of info, it's just like anything, you don't practice something, you can forget. Also there was a randomized controlled trial done that shows this is comparable to face to face training. This is the study published by the European Resuscitation Council. Even if you disregard that, I think it's fair to say it's better than just consuming info from say a youtube video.
If you're on your PC you can use the site https://www.lifesaver.org.uk/
or if you're on mobile there's the lifesaver app Google Play , iOS
Great game