I've been looking into what makes a great game lately, and I think I've found it!
First, let's look at a few popular games and compare the similarities:
Here's a few:
Flappy Bird
2048
Piano Tiles
Dota 2
Candy Crush
CoD
See the defining characteristic? No?
That's because there isn't one.
Each of these games is totally different in gameplay, size, budget, everything. Why are they all so popular then?
Did Flappy Bird just 'get lucky'? No.
Actually, there is one thing that all these games have in common, they all prompt Cognitive Flow in the player.
What is Cognitive Flow? Here's a few links to get you started:
The Psychology of Flow
What is Flow
Gamasutra
Wikipedia
Basically put, it's this:
When the players skill is equal to the games difficulty
gamasutra wrote: "In the 1970s a psychologist named Mihaly Csikszentmihalyi experimentally evaluated Flow. He found that a person's skill and the difficulty of a task interact to result in different cognitive and emotional states. When skill is too low and the task too hard, people become anxious. Alternatively, if the task is too easy and skill too high, people become bored. However, when skill and difficulty are roughly proportional, people enter Flow states."
While in these states, people experience:
1. Extreme focus on a task.
2. A sense of active control.
3. Merging of action and awareness.
4. Loss of self-awareness.
5. Distortion of the experience of time.
The experience of the task being the only necessary justification for continuing it.
Sound like Flappy Bird?
Csikszentmihalyi also outlined four characteristics found in tasks that drive an equilibrium between skill and difficulty, thus increasing the probability of Flow states. Specifically, these are tasks that:
1. Have concrete goals with manageable rules.
2. Demand actions to achieve goals that fit within the person's capabilities.
3. Have clear and timely feedback on performance and goal accomplishment.
4. Diminish extraneous distraction, thus facilitating concentration.
If you look at that list I showed before, you'll notice every single one of those games fits the criteria perfectly.
Flappy Bird:
The game is ALWAYS just that tiny bit harder than the player. It is has a very concrete goal (beat your/your friends high score), the player is capable of achieving that goal, there is very clear feedback on how well you're going, there are no distractions.
2048
Doesn't matter how good the player is, the game is just a little bit harder... Until you finish it. As soon as I finished it, I uninstalled it straight away, the game was no longer a challenge.
Piano Tiles
Again, doesn't matter how good you are, the game is harder.
Dota 2
Same again. One of the most addictive parts about games like this is the losing. When you think, 'oh no, I lost, I'll do better next time'. This happens when the player is almost as good as the game!
Obviously there are other factors involved, graphics, gameplay etc, but the difficulty of the game vs the skill of the player still comes at no.1
Good luck on your next game! Hope the links are helpful