IMO, if the minigame is inspired by Mastermind, then the rules are going to be much too complex for the type of interaction comfortable in an RPG or VN. Games either draw players because of emotional involvement (caring about the characters and their story) or intellectual involvement (trying to solve a hard problem). Those two motivations tend to be antagonistic, and attempting do do both in the same game tends to push back both categories of players, and turn the game into work rather than pleasure.
Let's not forget that the level of combat complexity of most acclaimed RPGs or even action and FPS games is at the level of multiple rounds of rock-paper-scissors. And you can in fact get to very interesting game dynamic using such a simple [ A < B, B < C, ... Z < A ] set of rules (like rogue vs warrior vs mage builds, or elemental magic combos).
In the end, the minigame *is not* the game :D It's not why people are going to play this, its only role is to add to the immersion in the game itself.