Thanks for all the comments as usual, you guys are the best and you all keep me motivated to get results each week! My focus has been slipping lately so I've started experimenting with the Pomodoro technique to get back on track. We'll see how it goes!
I think that's perhaps the downside of approaching a project like moonman "properly", i.e., applying good software engineering principles, refactoring the codebase regularly, iterating, integrating user feedback... as opposed to the quick and dirty way. You'll sure end up with a much more (re-)usable code base but the cost for getting there is that you're exposing yourself to the same old, same olf for a lot longer. I mean, the first mm post to this forum was 2.5 years ago -- I think it's only natural to burn out after such a long time. (By the way, I'm not advocating the more hacky "held together by spit and duct tape" approach here which will probably not get you past simple projects either.)
But don't forget that the game has *really* come a long way in that time!
I do remember that maybe half a year ago you posted here about self-doubts what the game would actually be about. Of course, you've had your background story with the different moons laid out for a long time, but you were wondering what the actual game play would be.
I guess there's a caveat hidden in a situation like that which is important for all game developers. Namely that if you choose to go by a more exploratory style of development like you have with moonman, that too easily you can invest enormeous effort in time into things that distract you from defining the actual gameplay. Just look at the various threads in this forum where very skilled graphics designers post conceptual gifs that look really awesome and that inevitably evoke "take all my money" responses... just to be shut down again after some time because a visually exciting demo doesn't equal an interesting game.
This is not to be confused with the situation in which you *know* already very well what your game is actually going to be like, and there's just so much left to do to get there that it overwhelms you. For that situation, I guess it might actually beneficial to have the possibility to work on different parts of the game in parallel to avoid getting stuck in one part. (For instance, after a months of tweaking the lighting you might really enjoy working on the main menu, etc.) As long as ypu're not in denial and working on different parts is just a way to avoid facing the real issue at hand, namely: "what is the game?"
If you have the answer to that question then it might really help to have different parts of the game that you can switch between to keep yourself motivated. If you only do the latter to avoid facing the question, you might still have a good time but you're probably not gonna end up with an actual finished procuct.