Posted September 27, 2015
low rated
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To put it another way, in an RPG, the player tells the character what to do rather than directly controlling the character herself. That distinguishes RPGs from, say, action games.
Also, don't forget that non-RPGs have leveling systems in some way (for example, powering up your whip in the original Castlevania).
One more question: How would you classify a game that is similar to a typical Dragon Quest game, except that there is no leveling system (but combat is still turn based)?
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The difference in my interpretation of an RPG from say, leveling up a weapon in Castlevania or Super Metroid, is that these other games focus on improving equipment but not necessarily the player's character. Therefore, growth becomes less individualized in the context of these other games as the player cannot change fundamental aspects of their character, limiting the degree to which a player may actively engage in "role playing" . Of course there are many exceptions to this rule, and genre boundaries are routinely blurred making the whole business of defining the critical elements of an RPG somewhat difficult... To side step this whole issue, I simply think of RPGs (or RPG-esque games) as having some form of stat/level growth. :p
Finally in regards to your last question... I can't think of any game in which a player might engage in a system of turn-based combat without actually experiencing the rewards of stat/level growth. Heck, even strategy RPGs rely on some form of character growth to improve a player's units over the course of the game.
Also, I should point out that there are RPGs where growth isn't "individualized" as you describe it. Dragon Quest 1 and 2, for example. Also, Final Fantasy Mystic Quest (though that game has some interesting mechanics that aren't obvious, like the fact that Life acts as an instant death spell on enemies).
Also, what about Gradius (and similar games), where you get to control how your ship powers up?