To anyone who's worried about having to do multiple playthroughs of the game to get all the scene, you dont have to. Just finish the game once and there should be a white crystal in the memorial dungeon that unlock all scenes, either temporarily or hard unlock.
If you're looking to run through the game as soon as possible, go very easy mode, stack up on dynamates early on to clear out the toughest mob in each levels. All levels should have this kind of mob, and it is always guarding the shortcut and should be accessible from the start of the dungeon. Don't worry about being under-level, and always sell the loot for money at the guild reception outsidde. After you acquire the bow, stack up on arrows instead (and keep acquiring the better bows of course) and spam it instead of dynamites. I tried it earlier and got through the game in 5 days under 2 hours. Also carry with you like 5 scrolls to tele back in order to stock yourself up and restore all health/mana; you can avoid resting this way.
Granted, a lot of the h-content of the game lies in the immersion and fantasy, as the sex animation is pretty much copy-paste, except for the main 5 heroines.
