When you finish an Anime and discover that there is a legit Hentai version with the same characters it is kind of hard to resist watching it too... Especially for a Mahou Shoujo Anime with the cute girls in cute dresses... Story: The story is pretty similar to the non-Hentai version "Magical Canan". Some "seeds" transforming people in evil beings must be collected by magical girls with their partner. Since this is a Hentai you can imagine what a lot of the time will happen... The good thing is that the story is well split over the 4 episodes making the watching experience a lot betterthan some Hentai where you clearly see that they simply add episodes without watching a decent overall finished plot.
They found a good balance in this Hentai between story and H-Scenes. The scenes aren't too long and they allow a lot of diversity.
To be honest I enjoyed the story more than in the non-Hentai version... Simpler, short, more entertaining and a lot funnier.

Art:
Pretty good for 2000.

Sound:
Nothing to complain with the Japanese voice acting and effects. There is a English Dub but I wouldn't recommend using it. I tried watching it with a Dub but it's really awful.

Characters:
Nearly every character type you want to have in a Hentai is there. Every relevant girl gets her H-Scene. I am not the biggest fan of the transformation form of the main girl but well the rest is more compensation than enough.
The green possessed monsters going around raping look a bit silly but it's acceptable.

Tags:
Mahou Shoujo, rape, Futanari, tentacle, monster, orgy
Uncensored version available.

I recommend watching the non Hentai Anime first. This way I enjoyed the Hentai more. All in all this Hentai is an entertaining good watch.