@Gallas
Your posts genuinely confuse me.
Let me be clear, here.
Even if I were to accept your premise of "the only useful feedback you will get is video of people playing your game", it comes with a million problems.
The short list:
1. Unless you're taping the expressions of the user on top of the gameplay actions of the user, it's nearly useless.
2. Watching how a player "plays" the game only indicates technical problems most of the time. It doesn't highlight "the game isn't fun" problems in the slightest.
3. Without voice to accompany the video, it's also fairly useless on its own, as you can ascribe your own confirmation biases to whatever the player is doing (which a TON of devs in the AAA industry currently do, and makes gamers think they've lost touch with reality).
4. Video of the person playing really doesn't help "narrow down a problem" all that much. It is entirely possible to watch a player receive the information you provided them as a dev for how a system works, how a skill works, or even how to beat a boss... and then have them not do that thing. Then, you're stuck figuring out why they didn't do what you intended. Did you word it poorly? Does it not make sense in the context of the game? Is it easy to forget? Does the player just not want to be dragged around by the nose and instead wants more freedom? Is the player just looking for ways to break your game, because that's fun for them? On and on.
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Put simply, you really need to engage in THREE primary forms of feedback.
1. Written/Video Essay reviews of your product. If you can't figure out how to parse a simple sentence like, "I hate this boss fight" and figure out where that boss fight is frustrating without asking a question... That's a "you" problem. It speaks to your ability to parse feedback to begin with or even to understand people in a general sense. This makes it easy for you to tell where the "quit points" of your game are. As in, the usual frustration points.
2. Gameplay footage. This is useful for finding technical issues or even signposting issues. This makes it easy to tell if everything your game is "functional".
3. Being able to see the facial expressions/body language of the player. This is useful for figuring out "if your game is fun".
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Now, there are also "analytics" in term of feedback. These are useful in other ways. Basically, the ways in which you can track player engagement and retention of the audience that will NEVER leave you feedback for the game.
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I, personally, engage in those four methods for nearly all my playtesting. It's my job to figure out what all the data means in order to create a better experience for the players. A "functional" game is usless if it isn't fun. It also is useless if it drives off players "out of frustration" or even "boredom".
Basically, you are saying that you have no idea how to actually parse the "quit points" of players and find it useless as a result of your own issues as a dev. Then, you are stating that the only "feedback of value" to you is just the sort that tells you if the game even functions or not.
This stance is confusing. I don't know why anyone would hold it. Same as I'm perpetually confused by people refusing to parse other forms of feedback, or dismiss them outright, because they "don't agree with them" due to their own dev issues.
It's feedback. Learn to take it, examine it, and make a better game. If you can't figure out how to do that, then you ask someone how to do it so they can teach you. If it still doesn't make sense when it's been explained to you how to understand feedback... then maybe GameDev just isn't for you. Maybe you're incapable of learning critical skills to creating a "good game".
But, the one thing you never do with feedback... is make excuses for why you don't listen to it. Or why it's "invalid" to your process. Because that's thirty flavors of arrogance that usually results in those devs going on crazy tirades on Steam and getting review bombed for just being utterly incompetent and terrible people.