This is originally from the blender game kit 2nd addition, but I summarized it and I think it will be useful for new gamers.
The Toy aspect of a game refers to the immediate fun of just playing it. You don’t need to think and you don’t need to read a huge instruction manual.
Note: This dosen’t mean that such games don’t require skill, but that you can immediately have fun in them.
The aspect of the game that makes you forget you are playing it. Realism plays a large role in this. Flight simulators are a good example.
This aspect is the degree to which the game gives you a goal. Goal games are often low on the Toy aspect because they often come with thick manuals and strategy guides.
This is not technically part of the three but it is very important. When you create games, you will have to strike a balance among the Toy, Immersive, and goal aspects of your games.If you can create a game that has a high degree of each aspect, you’ll most likely have a hit on your hands!