Simplexity is the fact that something is way too complicated for a simple task. And this is the exact thing you want to hunt in a game design. The player has to do things, or is guided to do things or is able to do things. But, he may have small tasks before this to complete this step.
Like in project managing, you can view a game as small steps to reach objectives, using tools that the game provide to you. These steps often provide choices : “will you use skill A or B to solve this puzzle ?”. And those small choices really matter, because if you have to use A + B + C to solve the puzzle, why wasn’t there a tool D to simplify it ? Did the choices A B C had real meaning and were engaging for the player ?
I’ve one example that would stay forever in my mind about simplexity : the game Hundreds by semi software.
There are circles, with a number inside it. If you touch the circle, it adds one point to this one. If the total of the all the circles are 100, the level ends.
It looks like a little complicated, and there aren't all the rules. But it is fantastically simple and deep. In fact, I consider it to be in the right “simplexity” for a puzzle game, because you have enough rules for it to have variations, and not too low to be short on gameplay. The game also provide different senses : touch, light counting and mental calculation, view of shapes. If you can make the test, take 10 different people and let them play this game without saying anything, on the first level. They will have behave differently, some will go by small touches, some will blindly tap all the screen, the other will do things you've never expected.
That’s a consequence of simplexity : approaches. If the game is too simple, there will be only a few approaches. With a too complicated gameplay, there will be hundreds of differents approaches, many will lost themselves in the path. But with the right depth of gameplay, there’s the sense that personnalities can apply, yet these interactions could have been “previewed”.!
Simplexity can be applied to any field, let's take video game production for indies. When you’re young and inexperienced, you try to do AAA FPS MMORPG 3D INTERNATIONAL. And through the ages, you discover that there are core mechanics. Core experiences that haven’t been explored yet. It becomes clear that simple projects can also be really entertaining and rewarding to make. As an explorer, you can try to reach India for new lands, though there are small caves beneath us that may containg golds and diamonds.
You can also link this notion to pixel art. Some pixel art games are state of art, even if the squares are THAT BIG. Because number of colors or complicated draw aren’t quality nor depth. A good draw features harmony, right palette, fluency, evocative items, and more
“KISS : Keep it simple and stupid”. It’s a basic IT tip, yet we can give it a new sense in game design. It’s not because it’s stupid that it has no depth. It’s not because it’s simple that it won’t be fun or efficient. Games can look really simple and easy to master, play, yet being incredibly deep.