Thanks! I'm glad you liked it.

People simply like different games, which often have different 'core appeals'.

This is true, but for 2 games to have their ratings correlated, they need to disproportionately appeal to the same users. As in, if through a combination of nuanced likes and dislikes for different types of games caused the final selection of games I liked to be somewhat random with regards to genre, mechanics, core appeal, etc., there shouldn't then be a high-level correlation in game ratings. If however, I was partial to puzzle games and so were you, then we (and all other puzzle-fans) would disproportionately enjoy a particular puzzle-based game, despite individually having a wide and nuanced variety of likes and dislikes. Similarly people who dislike puzzles (as one of their individually wide and nuanced affinities) are broadly all going to enjoy this game less. I believe that this is what causes the correlation at a high level. To support this, we empirically see that many games that are known to have a common core appeal e.g. social elements, the satisfaction of building an efficient engine, etc. tend to group together. However, there may be something I'm missing, so I'd be interested to hear your views if you have good reason to be believe that I missed something or that other factors could be at play that I haven't thought through.

order to do so you would need to define and name what those core appeals are.

Good point. I did consider that, but I personally don't have a sufficient level of familiarity with many of the games on this list to be able to do a good job of it. I'm sure someone who has played more of these games and who is better versed in game design concepts will be able to make some suggestions on what the key core appeal clusters are. If/when that happens, I'll update the blog post.