
I'm guessing that Konami decided to priotitize the four-player arcade version. Still kind of a shame given all the extra bosses (like Bebop and Rocksteady, and Slash) and levels that got added to the SNES version. I also would have kind of liked it if the NES Arcade Game and Manhattan Project had gotten online play. The NES game had extra content added to it as well, to lengthen the game and make up for the NES's inability to match the arcade's graphical fidelity.
Hyperstone Heist, I've noticed, is a lot stiffer than the SNES game as well. The action is nowhere near as smooth.