DISCLAIMER: I'm not a very succesful YouTuber, so my feedback may be of little worth, but I'm replying anyway because "any suggestions are helpful".
I've looked at the first two minutes of your last three videos (Battleborn part 1, Tube Tycoon part 1, Minecraft Murder | Return of the Butt Stabber). I'm surprised that Battleborn has the lowest retention, I think it has the most pleasant opening out of the three! Anyway, here are my observations, for what they're worth:
1. In the Butt Stabber, you start with a highlight: good. Presentation and entertainment theory, from what I know, suggest that it's really important to start your presentation/video with a reason for people to be invested. If possible, your entrance should be to tell what the video is going to be about (see: PBS Idea Channel) and/or why we should watch it and/or something to show that it's going to be fun(ny) and/or anything else to intrigue us (see: Vsauce). Shoving a funny moment in our face immediately is a fine way to do this.
2. Then comes the intro cinematic: maybe not so good. I'm not really sure what your intro branding cinematic adds, since we can already easily see who we're watching. Your intro cinematic, at 10+ seconds, is very long in my opinion. In the Butt Stabber case, you present the high point of the video, then give us ten loooooong non-action seconds to decide whether we want to watch this or not. You really don't want to give people more than a few seconds to think about that, if any seconds at all (the vlogbrothers are very good at getting to the core of the video before giving us any time to consider if we want to watch it or not). In fact, I used to have an intro sequence because I thought it was 'common practice', but I completely dropped it, because it was probably just counter-productive at this point. If you're bent on having an intro sequence, though, have a look at the one by the Game Grumps: it's catchy, it's fresh and original, and more importantly, it's very short.
3. Consider speaking more softly during the intro, actually. I do fear, if I may call upon my Dutch hounesty, that your voice may indeed be one of your weak points. It gets a lot more natural and easy to listen to around the sixty second mark, it seems. I'm fine with your voice throughout most of the videos (or well, the two minutes of the three videos I watched). But when you're speaking as loud as you can for the intro, it becomes a bit jarring and unnatural. This was a lot better in your Battleborn video: the reduced volume of your microphone feed made it less jarring, and the presence of a friend made you seem more natural.
4. Consider finding your own special hook. As a gaming YouTuber, you're in a very saturated market. If you're going to be playing games that are very extensively covered, like Minecraft and Bloodborne, chances are people are going to very swiftly decide that they can find someone 'better' who's playing the same game. You could consider tracking down some more niche games, or to invent creative little twists on the games you play so that you play them in a way no one else really does. (see: ProJaredPlays' 'interactive' playthrough of XCOM: Enemy Unknown). Try to figure out something fun and fresh and new, and start the video off with a short, well-written and exciting introduction to your unique play variant.
All the best to you mate!