A game should probably have four things: A sense of forward progression, some level of uncertainty or surprise, accessibility, and a challenge of some kind that can take the form of resource management, reflexive skill, explore-and-find, deduction, or any combination of the above.

There are probably games out there that don’t have all four of them, but I suspect that all widely-loved games share these qualities.

Forward Progression: The player should feel like something in the game is changing as a result of their actions, and that change should be permanent in some way. They could advance the story, increase the power of their character, or at least have some visual or auditory change occur over time. This enables a feeling of gain and accomplishment. Sometimes this feeling is enabled simply by the player getting a sense that they are themselves improving their skill at playing the game.

Uncertainty or Surprise: A game where the player knows exactly what’s going to happen isn’t much fun. There are games that are fun the first time, but then having been beaten the player will feel no need to pick it up again. This feeling is usually the result of a game either being unfair(in which case their frustration is a certainty and thus is not surprising) or the result of a game being centered around story or environment with no other variation. While uncertainty can be enabled via blunt randomness such as dice rolls, card draw, and procedurally-generated worlds, uncertainty can also occur as a result of player input.

Sometimes a player will enjoy playing a game they’ve already beaten because they are uncertain of where their skills have left off, and want to see if they can beat their record(which ties into forward progression, too). This is why games like Mario can still be fun to play even though there’s no real randomness to speak of intrinsic to the system(not to mention that in Mario and many other games, the state of the level depends on the way things are spawned in, often the result of the rate and timing that the player loads them via their forward progress). In multiplayer games, there’s an added level of uncertainty related to not knowing what the other players are going to do.

Accessibility: This is probably the most contentious aspect, and possibly the only one that can change outside of the game itself.

First, it is good design for any game to introduce its various mechanics piecemeal. A player should come to understand the basic workings of the system you are giving them before you ask them to use those mechanics in concert. This is why we have tutorials. You can ask the player to understand a vast amount of mechanics so long as each mechanic is introduced and presented in an intuitive way, and such that the complexity of the game increases gradually.

Sometimes, however, a game can be successful even when it is not perfectly accessible. Dark Souls, Dwarf Fortress, Crusader Kings 2, and many other games with rules that are deep and broad can find success. What’s interesting to notice is that these games became more popular over time after their initial release, rather than being immediately popular as many mainstream success games are. These games, in spite of their inaccessible nature, have become more accessible over time due to the internet and those who record information about the mechanics online. In other words, these games became better as a result of wikis, because they became more accessible to those who were willing to do google searches to find out how a given part of the game works.

While fan-operated wikis have proven to be a great way for new users to get into a dense game, it’s better if game designers take the careful steps to have the game provide all the information the player needs in a clear way. Budget permitting, of course.

Challenge: If accessibility isn’t the most contentious aspect of a game, challenge is. But before I touch on the controversies, I’ll briefly redescribe the types of challenges a game might have: Resource management, reflexive skill, explore-and-find, and deduction.

Resource management is a challenge of balancing things. I can exchange one thing for another. What’s the best way to do that? This isn’t just the mode of city building games, but any game where the player has something they must permanently give up in order to gain something else. Even RPGs and First Person Shooters usually have a little of this, either in the form of potions or ammunition.

Reflexive skill, naturally, is the challenge that tests the focus and motor skill of the player. Dodging, hitting, jumping, timing. This one is almost self-explanatory. What’s interesting is that this type of gameplay is usually the most punishing of all, and its tests are brief and fast and unyielding in their retribution. I like it, but I can see why not everyone would.

Explore-and-find is perhaps the most laid-back of all game mechanics. There’s a disorganized setting in front of you, and the player is either asked to find a specific goal or permitted to simply take in the details. Does not usually ask much of the player unless it is mixed with some other game mechanic. If mixed with resource management, exploring becomes about survival. If mixed with reflexive skill, it becomes a platforming game. If mixed with deduction, then finding the goal is much harder because it not clear where it could be.

Deduction largely amounts to ‘puzzle games.’ This mechanic is closely related to resource management in that it challenges the player’s logic and critical thinking, but the difference is that there is nothing inherently at stake. You might add a time pressure, but that begins to tread into reflexive skill on a mental level. A puzzle can be overt, such as in the case of any given Zelda game with its dungeons populated by various types of them, or it can be subtle, as in deducing the culprit of a mystery. Sometimes a puzzle can reflect a real-world challenge, such as building something to accomplish a task.

Right; with that out of the way, there’s a bit of controversy. There have been times when a game, found to be too challenging or at least more challenging than a potential audience likes might be reduced in difficulty after the fact. Often, this results in those who have mastered these higher difficulties to lash out. I think this is the result of an aspect of human psychology related to fairness…

Although it’s not logical, it’s the same psychology that makes people annoyed when they bought something expensive only for it to go on sale shortly after that. It’s probably also related to the idea of “having earned” an experience, and that offering an easier route after the fact makes the experiences of those who went through all that trouble feel disregarded, as though these newcomers don’t have the right to the same experience if they didn’t have to go through the same difficulties. Of course, this is not logical or humane. We shouldn’t force other people to struggle just because we have done so ourselves. But it is an aspect of psychology that clearly seems to exist, especially when it comes to things like experiences.

In games, I think this controversy is easily avoided by game developers including a very broad stripe of difficulty settings(or other means to surmount challenge such as by grinding) in their games. If the option is there from the beginning, the controversy won’t arise.