Look, i'm still young so i might be wrong, what i can tell you is
You finished a game and want to finish another one, which is more than what most developers in your situation ever do
You learned to make a whole game all by yourself, nobody made it for you, and not a lot of people are able to do that
The entire project was born from a desire to learn, instead of just trying to make easy money with a cashgrab, which is what some devs do
You did everything by yourself and i assume (based off of what you said) you've never done anything like this before your first game, and even "just" saying "it's okay" is a success, you started from zero, if you were still at zero, it wouldn't be "okay", but trash, which means you improved and learned a lot, so yeah, a success
I worked and worked... Well... You put effort into something you wanted to do... Doesn't sound like failure to me...
That doesn't mean i give up, it doesn't mean i won't try to improve... I'm sorry but i don't understand, you're not done yet, you finished a game, sure, but you're still making one, and who knows if you'll make a third or even more, failure comes when you give up, if you keep trying you're not a failure...
In the search for greatness i failed... Aren't you still looking for it? You're still making a second game right?
If you want to say you failed finding greatness in the first game you ever made, sure, but dude, greatness usually comes after lots of effort, time, work, sacrifices, improvement and LUCK. (Not saying you didn't put in lots of all of those things, it seems like you did, but luck is a core component imo)
I imagine throughout history, most likely there's been a few math prodigies that were too poor to even learn how to read and their talent all went to waste.
Or even if you are an amazing writer, let's say you manage to write the best story ever and you're a random dude, you think you have any chance of it being published? I think it's almost impossible
That to say, even if your product is insanely good, it's still unlikely for it to be a huge success
Regardless, you wanted to make something good, you should probably make something YOU like, everyone has different opinions so you'll never make everyone happy, you'll always have people complaining about something, and you'll go crazy trying to figure out what people want, but the truth is, they most likely don't even know it themselves... Doing something you want to do and having to change it completely to do something someone else wants makes it so that you'll end up making something completely different and not what you like, you'll probably start hating doing it after a while
I personally think that if you do something like this, where you're passionate about it, you have to see it differently
Not like, "this is what i made, do you like this?"
But like "i'm making this, you can enjoy it if you want, if you don't, have a great day"
Do things for yourself, not strangers, otherwise you're doing something for someone else, not yourself, and you have no obligation to...
Of course feedback is important, but you have to learn (even if extremely difficult) to differentiate from objective improvements to personal preferences, which not everyone can do, most people can't, including myself
You can't reach greatness in a single step, to climb a mountain you need to take a lot more
If you truly wish to reach the top, don't get discouraged if you're not already there after a bit, if it was that easy i'm sure lots more people would make money this way (not saying you do it for money, but some people do)
You've already taken lots of steps, keep going, if you stop, all these steps will be meaningless, and in the end, even if you fail, you'll know you did everything you could have done, and you won't have any regrets
That'e just my opinion of course, but i feel like you're being generally way too negative, at least towards yourself, i'm not saying your games are great because i have no clue, but you really tried, and personally i can't say you're a failure if you try
Not a lot of people deserve to be called failures, you're not a failure if you fail once at anything, otherwise we'd all be failures since nobody is perfect, and at that point, if we all are, nobody really is
Hope you'll think about this, have a great day and good luck with your projects!