The fan-made Streets of Rage homage released earlier this month after eight years in the making was recently pulled at the request of Sega. The original maker of the 16-bit Streets of Rage games says it took action to "protect our intellectual property rights." Sega's full statement is here.
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Here's a different theory.
Perhaps Sega WANTED these guys to get the game out.
THEN "legally pull it" to save face.
We're both winners! The game is out, and Sega doesn't look weird with them being free about their IP.