Please give your opinions on staying with-in genre types or breaking out of genres in games.
It seems that players really like type/genre games. The term “Rouge/Rouge-like/Rouge-lite” are all over the place. Nevertheless, I am not focus on one term. While it may be impossible to escape the known genres of games, my point is that players seem to like games that are minor variations on a game type/genre.
A designer can add features and bend or selectively change the genre rules, but only to an extent. You would think that genres had limited core rules and that a designer can build whatever on top. However, this does not seem true.
Please let us exclude series games (Assassins Creed 1-X, ect.) in which a base design is only meant to be modified small amounts and setting and story changes are the larger iteration factor. Are designers forced too not deviate from the type to greatly? Adding or modifying one or two elements is ok. Massively breaking the type would result in wide rejection by game players.
I have a theory, players select genre by preference and earned-skill. Earned-skill being a familiarity and time earned talent using the rules of a genre. In other words, players, play genres they are good at and avoid stepping into other genres were they must start over and climb the earned-skill latter again. Of course, it is just a theory.
To me this helps explain the almost-clone like creation of games. Stepping out of the mill can create stand out game that explode in market sales. It can give birth to new genres or sub-genres. However, more often than not, it seems to kill a game.
Do you believe that there are rules that cannot be broken? What would those be? Do you believe players are willing to learn games that change the very core rules? On the other hand, do you feel that forcing the players too far out of the well-treaded path will result in game rejection? Do you feel games can break a core mechanic, without breaking other genres cores, resulting in a failed attempt to hold to a genre ( I think adding the gravity power of a.k.a JJ and BUM, but holding on to the core platformer that the new mechanic never really fits into.)?

Thanks for the feedback
Mal