If that's all that required as similarities for one game to resemble another, then there are maybe one to four Ur-games on the market and throughout history. That's a pretty steep simplification of ED's system, and effectively allows for a good portion of the historical marketplace to "just be D&D." And that's on system alone. The setting is pretty drastically different from the most common D&D settings, with the possible exception of Dark Sun. I can't speak to how it would work with Cortex (as I don't know that system), but Earthdawn really doesn't match up that closely to D&D's system, let alone setting.I thought Earthdawn was very D&D-like back when it came out. It just had a history for the dungeons and the nasties therein provided in the game. It has levels. It has XP via delving. It has classes. It has spells that while they aren't limited in terms of 'slots per day' are limited by your ability to link them. One thing we did like was magic weapons that could grow in power as your legend grew. Actually, we liked quite a few things about Earthdawn, but it being amazingly different from D&D wasn't one, because it wasn't.