Hint 2: It was made by Tengen and there are two "versions" of this on the NES, but they are exactly the same. One is an official Nintendo-licensed cart (aka. regular NES cart). But they also printed unofficial Nintendo-licensed carts (Tengen had problems with Nintendo in the past), which look very different from the regular ones (this one is colored black and is shaped like an Atari 2600 cart would look like).
What if the world had no Streets of Rage?