OK, finally through this one. In general I enjoyed it, these "big list of bite-size topics" books tend to be easy and enjoyable reads.
Regarding what others have posted thus far... The Western bias angle is definitely something I hadn't considered before, a good thing to keep in mind whatever you're designing, I think! And cursor 10... that's a blast from the past! I remember playing that one during high school lunch!
The usefulness of this book was definitely a shotgun spread against a number of different disciplines and sub-categories of game design in my opinion. Many of them obviously skewed towards physical objects, but a lot were also straightforwardly applicable to UI design. The accessibility breakdown was a good one to keep in my back pocket and refer to later, I think. A few other piqued my interest...
Classical conditioning was an interesting one for me, because it seems to have such an obvious application to game design that I've certainly seen used many times, but had never directly associated with psychology in that way. The most obvious example I can think of is the Zelda jingles that play when you unlock a new area or get an item, or perhaps more aptly the sounds that play when you have a timed objective. I think it's pretty safely a part of the game designer toolset at this point, but it was a nice little revelation for me to associate the "game thing" with the psychology term, and a good way to remember to properly manage player understanding and expectation with familiar sounds and events.
"Common Fate" was another interesting one to me. That was the one where the groups of "X"s and "O"s moved around, and are associated into two distinct groups because of the direction of their movement, and not the actual shapes of the letters. I think the idea of being able to tie together disparate groups of objects by their behavior could be a very useful tool to a game designer... although admittedly I wasn't able to tie a bow neatly on this one. Maybe somebody with more experience could build off of this a bit better, but it was still pretty interesting to me.
"Confirmation" was another one that I felt might have some good practical use. The basic example was a "are you sure you want to quit" dialog, which has an obvious analog to "are you sure you want to overwrite your save." But I thought it had other potential applications to gameplay. Maybe it's not a perfect example. but I was playing Deus Ex for the firs time recently, and I noticed how long the animation was for taking the rocket launcher out of your inventory. I thought about how it was actually kind of nice, because there are 10 inventory slots, so if you accidentally chose the rocket launcher, you wouldn't be able to fire it off right away, and would have a change to undo your mistake. Finding similar opportunities for players to change their course of action would similarly be a positive change. Although you can go too far in the opposite direction and be an annoyance, but I suppose it's a balance, like everything else.
"Constraints" was another good one. Especially towards the beginning of the game. Although modern games have this problem to a way lesser extend than older ones, some games have a huge "what the heck am I doing" moment for new players at the start. Sometimes that can be part of the charm, though, for games that have many options and no clear path forward. Still something I'd like to keep in mind.
Anyways, there were a few more I kept track of, but that about sums it up for me, I guess! Nice book, it'll make good reference in the future I think. The only major downside is just how many principles there were, it makes it a bit tough to track down ones you liked unless you made a note of it.