'Popotan'; My takes...

UPDATE: A tip of the hat to Steven. He confirmed what I'd suspected was true for some time. THERE ARE INDEED TWO VERSIONS!!!
The early release has the numbers 12343, 12344 and 12345 on ''the shiny side'' of the discs themselves. The later release has the numbers 12343, 12344 and 12346.
That is the version I have. When I saw the screenshots that are NOT SAFE FOR WORK, I compared them to what was on my DVDs. There are differences though not as many as I initally thought, but they are indeed different.
On the 3^rd disc I can't even match the time coding!
For those playing at home, I used VLC running on XP MCE to watch DVDs.
NOTE: VLC makes screenshots a breeze, but it outputs them as .png files. Load the pic into your favorite editing software (MS Paint will do in a pinch) and resave the pic as a .jpg .
Everyone will thank you for doing so. I make mistakes so you don't have to.

I had no influence on changing Steven's rating of it from 'one star/thumbs down' to 'two and a half stars/thumbs up'. He did that on his own.

First I need to clarify what Steven got wrong in the development (and marketing) of the series. It was plainly developed for Japanese TV first. He claims in his review (and other writings) that the series was derived from an X-rated hentai game that's not available in America (and VERY likely won't be).
In a recent post about what is quite possibly from the hentai game Steven says ''Still no explanation of that wrecked spaceship though.''.

Here's your explantion Steven: The footage makes perfect sense for a sequel.
In the series, the overall plot arc spans between 1970 to roughly 2005 (the house not only jumps from location to location, but from point in time to point in time). In any sequel the story would have to move into the future.

This is likely the ending of a potential sequel of some sort.
Here is my guess on how the story would go: Somewhere in Japan in roughly 2035 the spaceship teleports into Earth airspace to teleport (''jump'') the house. Tragedy strikes in the form of the spaceship teleporting directly into the path of a large rocket or (more likely) an airliner. They collide, and the spaceship takes major damage. Unable to either teleport the house, teleport itself out of Earth airspace or even counter gravity, it falls to Earth.

As noted, it's immense.

Something that huge coming down would likely have the effect of an (at least) 7.0 earthquake.

This also explains the different house.

Viewed full-screen these buildings show cracks consistent with the effects of a serious earthquake. The Christmas shop was likely destroyed under or near the crashed spaceship. In the series Mea's job was not only to maintain the house/Christmas shop but to protect the girls as much as possible. (BTW, I'd say Mea is a cyborg) Figuring out something has gone horribly wrong she is duty-bound to evacuate the girls to safety. And does so. The different house is their new residence. With the overall story ending with Mea and the girls coping with life where ''The Quest'' is most definetly over.
I'll let others speculate as to what occurs in the hentai game itself.
As noted above I'm quite convinced the TV series came first but for the DVD release it was likely decided that it needed to be ''spiced up'' to encourage sales (to give those in Japan a reason to buy what has already been broadcast. As in ''COPS: too hot for TV''). Likely at the same time the hentai game was produced to use the nude scenes for both releases and also to take advantage of the marketing for the DVD release.
When it was decided to licence it for region 1 Genon took the DVDs that were already being sold in Japan, subbed it, dubbed it and shipped it to America. The version Steven saw plainly should not have left Japan.
Genon got wind of Americans reaction to what Steven calls ''the lolicon aspects to it'' and realized ''UH, OH, we gotta fix this!!!'' (simply to avoid legal issues). I'm guessing they pulled the early release from the market, inserted footage from the original TV show (removing most of the nude scenes) and re-released it for export out of Japan. That is the version I got for Christmas, watched and quite liked. And DO recommend.