I suspect there are some hidden details about that you son was playing and found it easy. Maybe he saw someone playing it and realized some easy play tactics. Maybe you explained him something. I don't know. But I suspect there was some details that made it not a blind first play for him.
The key to the game is getting to know the map. Once you become familiar with it, things do get easier. Kids do tend to pick things up quicker than adults! Maybe he's just better at it than you are? Sorry, but you're starting to sound a little bit jealous of a 13 year old kid. By all means offer feedback on the game, that's absolutely fine, whether it's positive or negative, I don't mind, but there's no need to start having a dig at the kid's gaming skills.
I find it a bit absurd to have to answer this, I don't see the point, but since you insist so much I'll do it just once. As I told you, my son saw the game and asked me to install it for him, because he liked it. He watched me play for about 2 minutes, no more. The only thing I told him was the objective of the game (which the game itself tells you), he saw that there were some coloured keys to open doors and I told him that one of the pieces he was looking for was in an attic (which the game also tells you!). From there, he went to his room and managed by himself to find the keys, look for the stairs upwards, go up to the attic, etc. All by himself and no more spoilers. And I assure you that after only three games, he knew the map much better than I did. I hope you'll feel more at ease now that I've revealed the 'hidden details'.
Haha, things that happen...
By the way, the game has crashed twice on my son's computer, the last time a few minutes ago when he was in the middle of a game. The error window said "Melkhior's Mansion encountered the following problem and will have to close: Referencia a objeto no establecida como instancia de un objeto". I have the log files, if you want to have a look at them.
Anyway, you know kids are doing 20 things at the same time on the PC, and they keep changing the focus from one thing to another, watching streams, talking on discord, etc. That may have caused the problem, but I don't know.
There is a crash bug that I'm aware of, it's probably the same thing. Can you email me the files from the log folder? My email address can found here... http://www.bitglint.co.uk/EmailContact.aspx
Thanks ;o)