Damn, it's been awhile since I've seen one of these.
First off, I'm glad you're still around and animating! Your work is always incredibly good, and yet it seems like you did this all solo despite it probably being your longest one ever, with some of the best animation and backgrounds that normally take a full crew ages to make. I feel like even if you told me you made something like this just to get paid, I wouldn't believe you, because your passion is clear in your visuals and animation.
Those backgrounds man, they were so nice. The house and rooms all planned out, the little 3 star doorway, the kitchen and little details. It's honestly really awesome, and must have been a ton of work. The ending didn't feel rushed at all, we just got scene after scene of random slice of life stuff with no predictable outcome that made it fun to watch all the way through. I also liked how you drew king triple D with the fluffy ruffle coat, and him having a bunch of tiny waddle dees. Also his letter having a bunch of crossed out spelling errors, very in character for him.
You're going to get a lot of compliments that'll just repeat anything I can say here, but I'm happy you set out to make something that was as much for you as it was for others, you've clearly been driven, and its nice to see passion in people's art and animation. Hope you have a good day famalam.