After much philosophy, I've identified 16 prime emotions, not counting the negatives separately. Note that I'm not done with this - I'm sure this isn't entirely right, but it's close, and someday I'll understand it all. Also note that I had to fudge the English language a bit, even to the point of outright reusing names, because English was not invented by philosophers.
(Note that the "future-minded" emotions like fear and excitement are actually reducible to these; they're just the partial-certainty forms: if you think there's a 50% chance that something upsetting will happen, you'll experience half the upset.)
|Gladness, Self-Pity||Own percieved fortune|
|Companionship, Loneliness||Sharing one's thoughts and interests with others / being unable to do so (footnote below)|
|Epiphany, Frustration||Understanding gained/lost|
|Pride, Humbling||Skill gained/lost|
|Empowerment, Disempowerment||Using power / Having no outlet for such (footnote below)|
|Engagement, Boredom||Applying one's skills and effort / Not having a need for them (footnote below)|
|Novelty Fun, Boredom||Change/progression, stagnation (footnote below)|
|Exhilaration, Restlessness||Being involved in big things / being irrelevant (footnote below)|
|Appreciation, Disdain||Experiencing good/bad works of art|
|Amusement, Disamusement||Humor, failed humor|
|Self-Esteem, Self-Hatred||Assessment of one's alignment with one's ideals|
|Satisfaction, Regret||Assessment of the result of one's actions|
|Admiration, Disgust||Other wills in accord/discord with own ideals (footnote below)|
|Validation, Embarrassment||Being seen by others whose opinion we care about as being the way we do/don't aspire to be (footnote below)|
|Empathy, Sympathy||Wanted prosperity of other / unwanted suffering of other|
|Schadenfreude, Anger||Wanted suffering of other / unwanted prosperity of other (footnote below)|
Footnote on Empowerment/Disempowerment: This accounts for the pleasure of physical exercise, but also things like the powerful feeling of the weapons in Halo 1 and the way a lot of CCG cards seem to appeal to an "awesome factor". It's also part of the enjoyment of winning at games in general (the other part being pride), and the enjoyment of customization.
Disempowerment is the frustration we often feel "at nature"; hence why empowerment (manifested in outlets like punching bags) relieves it.
Footnote on Engagement/Boredom: This can be understood as the "fun of trying", whereas Empowerment is "the fun of winning".
Footnote on Novelty Fun/Boredom: This "feeling of progress" notion is the reason why game players seem to universally enjoy mechanics like having levels be locked until they've beaten the previous level, even though from a logical perspective it seems like this is strictly worse for the player.
Footnote on Companionship/Loneliness: This also accounts for playing games with other people being almost universally much more fun than single-player.
Footnote on Exhilaration/Restlessness: This shows itself in a lot of ways, including getting to the climax of a good game or story, being on a large team and/or playing with stakes in a competition, and I think the enjoyment of spectating a prestigious tournament or similar is also a form. It can also show itself in more meaningful ways, such as playing an important role in one's real-world cause (although most people have little to no experience with that, myself included).
Footnote on Admiration/Disgust: The concept of "ideals" is one that took me a long time to pin down. I think it's "what you'd will if you didn't have a personal stake in it". So that's why you can admire someone for being closer to your ideals than you, whereas back when I just called it "other wills in accord with self", I couldn't understand how that was possible.
Footnote on Validation/Embarrassment: A lot of things are accounted for by this.
How compliments, condolescences or similar social idioms are often emarrassing to the socially inept (which I'm certainly one of). It's our fear of being seen as rude or ungrateful. This is supported by my experience that the effect is less pronounced or gone entirely when the onlookers are people whose opinion you don't care much about, or who you know will understand that you're just having trouble finding a tactful response.
The immense power of one-sided hostility.
The general concepts of "dignity" or "formality" are often a form of this. For example, slouching is a sign of comfort and so doing it while receiving grim news is irreverent. Everyone understands reverence on a conscientious level and so it affects their emotions even if they consciously deny that it has moral value. Similarly, if a heated argument takes place while eating, ceasing to eat while making your point gives you an air of dignity.
Of course, losing an argument or being the last one to solve a puzzle is often embarrassing, because it makes you appear less intelligent, and everyone wishes they were intelligent.
A few notes about things that aren't on the list and what they're composed of:
Gaming "salt" is self-pity turned into a more anger-like annoyance (through the means described above) + embarrassment, because we feel it when we feel we 'should' have won the match, but didn't because of something that we see as 'bullshit', so we try hard to convince everyone of the same so that it won't damage their opinion of our skill.
Gaming "tilt" (at least as I used to feel it) is frustration, combined with zero or more of a couple others: humbling (finding out I'm not as good as I thought), embarrassment (losing to a much weaker player), and losing rating is a trigger of both (since it's both how I measure my own skill and how other people measure my skill).
I think "grief" is composed of self-pity (from how much worse your life will be without the person), loneliness, and sympathy.