Well, if we're going that way, then before I got Dragon Warrior, I got Gateway to Aphsai (that's probably spelled wrong) for the Atari 800. That game was probably my first introduction to the Roguelike* (though the dungeons weren't actually randomly generated) and, for that matter, exploiting the (nonexistant) pathfinding AI of the enemies for cheap kills (enemies went on a straight line towards you, meaning that if you interposed a corner between you and them just right, you could take them out without fear of retribution. It's, technically, the first RPG I ever beat too.
*Yes, I know it's not a proper roguelike - for starters the dungeons weren't randomly generated, but it's close enough for government work.
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