I have a simple counter question for you: what do you want to do with those?
Personally, my take on this is if it's a hobby, you should do only what is fun for you. Nothing else. If it spells work for you, or a big time investment, then just forget about it.
You should not think of these projects as a sort of failure in any way. I have dozens, maybe hundreds of these things lying around or already discarded, and I don't worry about that for even a millisecond. As opposed to you, I am a professional developer, so these are my practice playgrounds. I toy around with new technology, interesting ideas, etc. and I never plan to make a huge kick-ass game out of it that hundreds or thousands of players will play. If you keep your naivety under control and start your projects without having such a dream, then not finishing it all up is perfectly fine. If you want something to show for the time you spent on this hobby, then you should maybe switch from games to graphic demos, i.e. switch to something with a much much shorter time-frame needed for its completion. But as you already learned - getting those last 5% done takes about as long as the first 95% took.
Finally, if you have any plans to turn this hobby into a career, then don't throw away the code. Just let it rest. Come back to your old code after a year or two for a very instructive experience. It will show you how much better you got in the meantime - the typical reaction to one's old code is "oh my.. did I really write code like that once?". And if you take the project on again, you'll get some valuable experience with regards to developing with legacy code bases. By the time you will have forgotten all of the intricate details, all of your great design plans. Your documentation may be outdated and your dependencies may no longer be available, etc etc. in short: you got yourself the real world deal. Be warned though: this is not even remotely as fun as writing your own stuff from scratch, so I'd only advise to go down that rabbithole if you want to get farther than it just being a hobby.
In summary: stop worrying. Adjust your view of what you want to get out of the hobby and accept the consequences.