6 + 7

6:

I think it's interesting to mention: "The primary benefit of basing your design around a single theme is that all of the elements of your game will reinforce one another since they will all be working toward a common goal."

I found this point to be the most important. Of course, the steps and all that are mentioned, but I think the emphasis on unity is interesting (no pun intended). Like If you have a game about bees and suddenly you are in the ocean- with no context- it's going to throw the player off. If you have a single theme and stick to it, it'll really immerse the player into the game.

7:

I also wanna highlight the emphasis on brainstorming in this chapter. I know I hate actually planning, but brainstorming is a must. When I was thinking of my game, I had to first think of what I wanted to do. Then, what's the plot? Is there a story? What are the levels? What do I name everything? From there, all the ideas flow. Then you just start writing and making maps!