Yeah, that's the way to end a series!
Hell you left me with this godawful feeling in the previous episode, but this is really the only way to end such a great mini-series. You follow a classic anime storytelling scheme, which really works! Sorrow-free at first, then when you get to love the characters you break them up and makes you feel miserable. Only to end it with a big bang in the end where all the characters come to enclosure.
Love how you add a little something special to it, like that the colors (the green scarve) have meaning in your story. Just like Schindler's List where the red coat was a key element.
In this episode I was impressed with the quality of the effects, especially the big hologram sign in the end. Really great looking, and I love the contrast of the B&W world with the colorful elements. It gives almost an Apple kind of look.
The music was fitting and drags you into the movie. It reminded me of Furi Kuri when the happy theme came. It radiates a similar feeling.
So to make this story short: You've done a great job! These are the things that make our live a little more enjoyable, and which reminds us why movies and animations are made in the first place. The final step (hehe) for you now would be to compile a complete animation of all episodes, bring it out on the web, dvd, whatever and let me and a lot of other folks buy it!