1 NTSC frame = 16.7 mS. MK is one of those games you can't compromise with on response time. Assume we both have a sega and some mythical XBAND modem with ethernet. So it takes about 5.7 mS for a light signal to travel from me near Detroit to you down in Naw-lins. Of course, your machine would have to respond to my machine, another 5.7 mS return trip. That leaves us only 5.3 mS for both of our sega's poor 68000 and Z80 to process our button inputs, crunch the game logic, and draw the frame; and I didn't even consider the overhead for the network itself. What's next? Retroarch online and a screaming fast CPU? Nope... even though it's peer-to-peer and even though you've got a fast machine... given the distance between us, it could be a crap-shoot on how many hops it's gonna take for a message to get from me to you... I've read latencies could be up to 1 second for a packet to come through. The outcome of the battle for MK master of the universe can't be questioned due to latency issues, therefore it probably can't be done over a network.