Pretty good art, there being a lot of animations helps it in that regard. The story with the two spirits and the future Avatar is pretty interesting. The characterization is as close to the original as it can get without forgetting that this in fact a relatively lighthearted porn parody. For those characters who had their personalities considerably altered, it is only played for the comedy factor, like Iroh.
The inclusion of separate routes between love and slave is brilliant, it not only adds more content to the game but it allows people that aren't too much into domination and degradation to enjoy it.
The addition of multiple OCs, besides there being more girls to bask in, makes it so the background world is more expanded upon. It would certainly be odd that the only characters one could interact with were random NPCs that are only there to give you items and quests. Now not only they do that, but they also let you use their bodies if certain conditions are met.
Which brings us to our next point, interaction, this game has a lot of it, in the form of many mini-games, some required to be played to progress, and a few extras just for fun. Even those mini-games that are forced on us never feel too tedious nor are they too hard or complicated. The most common of these mini-games is the recurrent battle system, which can be won very quickly just by holding the skip button and pressing the other action buttons in the keyboard or clicking with the mouse.
The game pays attention to reward you for playing most of these mini-games, so it's not like you'll have to grind a whole lot to get the sexual content, though it also makes it so you play quite a bit of them to get them so you don't blitz through the game in just a few hours. I personally spent like 3 days playing the game since early in the morning until late at night, with a few rests in between, and I still have to do the slave route of Katara. So the game is quite lengthily not just for the casual gamer but also for the more hardcore ones.
The game has quite a lot of charm in the form of humorous text and situations, with references to other games like Akabur's works and mainstream series like Pokemon as well as its jokes like the Fire Nation guards.
Finally, the most important, the fap factor. It is pretty high, not only thanks to the good art, resembling quite a bit that of the of the show, and animations, but also because of the constant dirty talk, which always makes it so that the sex scenes are never too mushy mushy like that of serious Visual Novels. People play this to fap, the game knows it and delivers it excellently.
As for the actual content of the sex scenes, most of them are quite vanilla, you're not going to find any gut-wrenching horror in here, I think that the most dirty thing in it is a little of golden shower, which is still pretty light compared to a lot of things out there. I think that the most exciting thing in this game is a little of x-ray coupled with impregnation, and a pregnancy sex scene.
Now for the bad things, there aren't many nor are they too important. But it would be the fact that a LOT of this game's scenes are awfully similar, but not completely identical, so the skip function of the game of course rightfully recognizes them as scenes that you haven't read yet, which would be all fine and dandy if the differences weren't just slight details in the text, with basically no difference at all to the actual sex scene taking place. This means that you are going to view a parallel version of a single blowjob scene like 7 times IIRC. 3 for the Love Route (regular, submissive and equality), and 4 for Slave Route in terms of progression. By the third or fourth time it gets frigging annoying. I cannot fault it too much since this is incredibly common and sort of like the point of slave training games, but still, annoying as fuck.
That being said, it still doesn't detract me from giving it a 5 stars rating. It is nothing short of incredible that this is still an unfinished game, whole other porn games have been made with just half of the content of this one, or even less. I cannot even imagine how it will be when it is finally completed.
Having finished the Book 3's slave route, I have to say that I'm amazed. It is nothing short out of outstanding that Book 3's slave route alone has more sex scenes than Magic Shop, Witch Trainer and Star Channel 34 combined. And not just the scenes, but also the girls as well, which amount to about 11, a great improvement over the 5 that were available in Book 2.
Though now this makes me wonder if all or even most of these girls are going to be available in the coming love route, since you fucked a lot of them via hypnosis, which was a recurring mechanic during this route. Something as rapey as that would be a little weird in the love route, more so because the choice that branches the routes was allying yourself with Long Feng to learn his hypnosis teachings.
One thing though that I have to criticize of this Book is the fucking obsidian, finding most of them is not that hard, but there is a specific one that can be a little tricky.
If you happen to finish the "Kill the Avatar" quest while there are other quests remaining, you will be locked out of them, the game saying you completed them all. The game never gives you any hint this is gonna happen, which is a problem because there are 2 quests that reward you obsidian.
I had progressed a lot since my previous save so I had to use console commands to give me the last obsidian I needed. Not the worst thing thing to happen in a porn game ever, but it was still an annoyance.
Every section has multiple walktrough fitting the original region. Honestly I would like to see more action with the side characters, well they still might extend those 
