Ronin: Spirit of the Sword

Ronin: Spirit of the Sword is a Flash game which can be found on Newgrounds. Is a first-person adventure game, divided in three parts, involving dungeon exploring and sword fighting. And also some seriously NSFW stuff.

You play as a blue-haired ronin, a swordmaster who's trying to recover an ancient, powerful scroll from the evil ninja master Red Fox. Captured by the ninja's minion, he's imprisoned in her mansion, but saved by a girl named Rei, who wants to end Red Fox's threat by any necessary mean. Together they join their forces to battle Red Fox' followers and stop her.

Tropes used in Ronin: Spirit of the Sword include:

Absolute Cleavage: Makoto (who's less revealing but does make her chest look bigger) and Ayame.
Action Girl: Rei, when she helps you out during the tutorial. Outside it, she seems to be more prone to some other kind of action...
Aerith and Bob: The various girls you can find in your way have all Japanese names like Makoto, Yuri or Ryoko. Then there's... Zelda. Partially justified, as she's blonde and possibly westerner.
Anti-Hero: The Ronin. Yes, he's up against the Big Bad, but nothing stops him for having some intimate fun with the scantly-dressed, buxom ladies around the labyrinth.
Big Bad: Red Fox the Ninja.
Big Badass Wolf: Wolves are described as the "ultimate melee bastard".
Bilingual Bonus: The girls you can find speak in hiragana, but they mostly groan or moan. Sometimes they actually say "yamete" (stop it!).
Color Coded for Your Convenience: Your ki attacks and character are blue colored. Enemy attacks and Red Fox are red colored.
Covert Pervert: Rei tells to our hero that she's having a bath. He promptly assumes that she wants him to peep on her. He'll also grin like a moron whenever he's "interacting" with one of the ladies.
Crosshair Aware: When an enemy is about to attack, one or more red circles will appear on screen, telling you where to place your sword to parry. Subverted with the Bamboo Fire Traps, as the circle's brightness warns you about when it's about to shot.
Damsel in Distress: Rei in the third act, when Red Fox scratch her with poisoned claws. And her hair incense is the only antidote.
A Date with Rosie Palms: Rei, for apparently no reason at all.
Family-Unfriendly Death: You can dismember zombies, cut off the legs of samurais and ninjas or split the wolves' heads apart. Red Fox's poison will make Rei's heart beat faster and faster until it explodes.
Fan Service: Lets see: scantly dressed/outright naked beautiful ladies, buxom young girls "relieving themselves", you take the pick. It also makes the game NSFW
Hot Chick with a Sword: Ryoko and also Rei.
The Immodest Orgasm: Rei, apparently. Also the girls when you select them.
Incredibly Lame Pun: In the end of the second level, about "seeing it coming". Mix it with Rei's hobbies and you get the joke.
It's Personal: When Red Fox poisons Rei.
Katanas Are Just Better: You can slice things with it, and parry swords, shurikens, claws, fangs and fireballs with no penalties. Picking up a Katana will also increase your attack bar.
Magic Knight: Your Ronin can also learn how to cast spells.
Ms. Fanservice: All the girls.
Ninja: Red Fox and her minions. The latters are clad in blue, can throw shuriken and know kung fu.
Nippled and Dimed: Nipples and everything else's clearly visible. That's why's not safe for work.
Our Zombies Are Different: Slow moving enemies, not really a threat.
Parasol of Prettiness: Makoto.
Playing with Fire: Red Fox can disappear into a pile of flames and cast fireballs at you.
Running Gag: Rei masturbating after each level.
Sai Guy: Red Fox dual wields sais when she's tossing fireballs at you.
Sarashi: Natsumi wears a loose one, which doesn't cover her nipples.
Stripperiffic: All the girls, except for Makoto (who compensate by having larger boobs.)
You Gotta Have Blue Hair: The Ronin.