A better storyteller than the anime version.
I reviewed Stepmother's Sin, Gibo's animated version, two years ago and I observed two major differences: (1) the characters in the game don't look much like their anime counterparts; and (2) the story here isn't nearly as dark as the anime. For one thing, I noticed that the women here a little bit more believable when they protest. Gibo is not as two-dimensional as Stepmother's Sin. You get to delve more into the characters' backgrounds for better understanding of the plot, which makes Gibo the superior storyteller. You can actually hear Misako's thoughts and how she slowly develops feelings towards her "son". Also, the woman obviously has a bit of substance between her ears. I mean, the first ending I got was of her filing a case against Yusuke for his indecent behavior. Go Misako!
The same characters are introduced: Yusuke Yagami, the protagonist; Misako Yagami, the beautiful stepmother; Mio Yagami, Yusuke's cousin and fuck buddy; and Shiina Kikuchi, Misako's daughter. Unlike the anime, where the end is tragic, the three women of the bishoujo game have different paths that could either be happy, depressing, or bleh. There are a total of 14 different outcomes, and you'd find yourself thoroughly involved, depending on which girl you're rooting for. Most of Gibo is about Misako, though, and none of the endings seem to be less than bizarre—even the ones you'd think were good.
One minor nitpick I have about Gibo is that the ages aren't very consistent. The booklet that came with the package says that Misako is 37 and Shiina is 18. But in the story, Misako declares that she lost her virginity at age 20 (hatachi). If she lost it at 20, then there's no way Shiina could be 18. Either they failed to correct the age factor and Shiina's real age is 16, an age considered legal in Japan, or Misako is lying.
This would've been the ultimate incest game, if it weren't for the fact that Misako and Shiina aren't related to Yusuke by blood. He bangs his cousin, too. (Although in some parts of the world, having relations with your first cousin is acceptable.) Still, mixing and matching the females, especially ones that are related, can somehow seem disturbing. Imagine, too, the convenience of Yusuke's dad being so busy with work that Yusuke can molest all three women in his house without any hitches. Hm. Perhaps "molest" isn't the word I am looking for. After all, Yusuke exposes his women to various acts of perversions like pee-drinking, whips, candles, ropes and the like. The girls also somehow manage to fall in love with him in some paths, despite his ocassional brutality. Yusuke must be one lucky bastard.
The music is poignant and somewhat touching, and the voice acting is excellent. Appreciation of the artwork is an acquired taste (I find Misako's hairstyle a bit tacky), although many of the CGs are exquisite. The backgrounds are rendered in 3D, giving the game a smooth texture. There's the Extra menu, which contains all the CGs, music and events in the game.
The gameplay itself isn't too bad, since you have the "Love" bar and the "Lewd" bar, wherein you can check if Misako's feelings for you borders on love or lust. There's also my favorite fast forward button. Other handy features are the Quick Save, Quick Load functions, and the buttons that let you move back and forth in the story.