Consider a few issues I've been wrestling with.
Issue #1. Though mechanics make up the core of the entire interactive video game experience, does the cleanness formula really reflect what I think it does when the mechanics fall short? Should it really affect a game's cleanness so much if a mechanic has a cancel or can be done simultaneously with another action? Sometimes I think not. But I do like how the cleanness formula is pretty cut and dry. And like I said, because cleanness doesn't express how deep, fun, complex, etc. a game is, I don't worry as much about how easily the score can fall for some games.
Issue #2. Individuality, the subcategory of mechanics design, is very tricky. Originally, I came up with this category with cleanness in mind. I reasoned that the interface design of a game gets complicated and cluttered when you can execute different mechanics with the same input method (typically a button). For most non-individual mechanics players can activate specific actions through differences of timing, pressure, speed, a combination of inputs, or a sequence of commands. Or the mechanics are like RUN and SHOOT (fireballs) in Super Mario Brothers in that they're mapped to the same button and activate simultaneously. In general a mechanic can be mapped to multiple buttons and still be individual. It's when a button activates multiple mechanics that we run into problems.
But what about Advance Wars? Or Star Craft? Can't you use the A or left-mouse button respectively to execute every action in the game? Does that make these mechanics non-individual? I want to say no, but I need clear reason. At first I thought that the difference between actions in Advance Wars and the RUN/SHOOT button in Super Mario Bros was a matter of context. Technically, the A button in Advance Wars is SELECT, and it applies to menu navigation. Every time you select a unit, the menu and potential gameplay actions change contextually. Then you select a mechanic or action that you want to carry out. Games that are abstracted to the degree of indirect actions or commands are typically like this.
Couldn't we technically say the same thing about the non-individual mechanics in any type of game. The B button in Super Mario Brothers is a RUN/SHOOT "select" button for Fire Mario. If you don't want to do these two actions at once, you need to DUCK and then hold the B button to not SHOOT a fire ball. Or when you have multiple units selected in Star Craft, if you don't want them all to attack (multiple actions) then you need to only have one "selected" to change the context. Or a Street Fighter example. The difference between Ryu's standing hard kick and a sweep depends on whether you're crouching. If you don't want to sweep you need to not "select" that option by crouching. In all these examples, we could say that the buttons are just a generic action buttons and the context of the game/character state determines the result. Does this view excuse these mechanics from being non-individual?
We can go further. The JUMP button in Mario is individual, right? But what about when Mario is underwater? The JUMP button turns into a SWIM mechanic. Both mechanics help Mario fight against gravity, but they're still two different mechanics. Does this mean that Mario's JUMP isn't individual after all? Not quite. Because you can only either SWIM or JUMP based on the way the wet or dry levels are designed, this contextual change is like playing two completely different games with no possible mechanical overlap (at least for the original SMB)? There's no way you should confuse SWIM for JUMP. After all, if a game offers two different characters with different move sets, we wouldn't automatically label the mechanics non-individual just because one character punches with the A button while the other kicks. Games like Wario Ware are filled with micro games with straight-forward, individaul mechanics. Just because the game offers a variety of micro games doesn't mean all the mechanics are no longer individual.
So when does context excuse a mechanic's individuality, and when does context count against it? Here's what I figure... (The following examples are written with simple on/off buttons in mind for primary and secondary mechanics).
A mechanic is non-individual if...
So mechanics in which the input context is preceded by some kind of state change with clear and unique feedback tend to be individual. Most mouse/pointer/stylus/touch based interactions with virtual buttons tend to be individual in this way.
Advance Wars: Days of Ruin. (Limited to the campaign missions) This is a great example of a game that's very clean and very complex.
1*(1*1) - 0 = 1
As you can see with Advance Wars, turn-based design tends to yield very clean gameplay experiences because without the pressure of real-time, players can perceive all the variables of the game state at their own speed while progressing at their own pace. Might & Magic: Clash of Heroes is another great example of a fairly clean turn-based game.