Another great example of how to make a terrible game.
Avalis Dungeon consists of entering a dungeon without cause, randomly walking through it until you encounter a "Sexy Monster" [yes, that's correct] and then choose to attack, use fire magic, or ice magic. There's no clue how to proceed, and when you GUESS wrong, you start it all over at the beginning...
Lesson #1: Games of no skill or rationale aren't compelling
In order for a player to feel connection or immersion in a game experience, there must be some sense of player choice that either involves rationality or skill. Avalis Dungeon, instead, involves GUESSING. Rather than being able to strategize an attack, or use some sort of skill in battle, here you guess X,Y,or B. Take your pick. If you get it right, you proceed. If you're wrong, start over again. Of course, if you're battling a Mermaid, I could GUESS that fire might work. But in this game, i could still be wrong... And when there's no apparent reason at work, or required skill, the player feels coerced by the game. Better just to roll a die and see what happens. Luck at least is transparent.
Lessons #2: Sex Appeal without context feels... um... like porn
Now I'm not categorically against pornography, though I wouldn't say I'm an advocate. But I can say this: if you're entire game involves watching scantally clad female monsters in their underwear, who when you defeat them seem to be wearing even less clothes, that's about as close to just reading a Fantasy version of Penthouse as it gets. If you're going to make a pornographic game, that's fine, but better to be up front about it. Otherwise, the player feels coerced.