MK1:
Genesis had low color counts which led to poorer graphics. Most noticeable was Goro's Lair which was totally redone and looked horrible. Also, the sound effects were cut back in number and made lower quality compared to the arcade, and the musics were considerably bad.
SNES had the colors and decent looking graphics. They also had rather authentic sounds and musics. They lacked blood and had editted fatalities (Kano ripped some grey thing out of you). The main problem I had with this was the controls were very sluggish. There was a definate delay between button press and action and for fatalities like Scorpion's (up, up) you could press up, up fast and he wouldn't jump, because of the lag.
MK2:
Genesis was horrible. They had garbled sound, musics were ultra low quality. The character graphics were extremely cut back. There was a feeling of higher speed that people always talked about, but I believe this mostly came from the dramatic loss of frames. Also, there is the same low color problem that leads to an all around blotchy look.
SNES had very rich, colorful graphics, but not arcade quality. The arcade for MK2 had enormous and highly detailed characters, if you can check it in the arcade you should because the game looks unbelieveable. The sounds and musics for SNES were well done, again, not arcade quality, but fantastic considering how other ports looked at the time. The lag in controls was solved, and MK2 for SNES had what I consider very nice controls, leading to some rather quick gameplay, in some cases it even felt a little quicker then the arcade to me.
MK3:
Genesis again had low colors and bad sound. It had some speed, but really the SNES version, by this point, had the speed it needed as well.
SNES version was showing its age as the system got older. It was not as impressive a port as MK2 was IMO. Definately playable but with some major tweaks in gameplay that seemed rather pointless, especially around the juggling.
PSX version was very good, with high quality graphics, all the sound effects I believe, and CD audio tracks for the musics. The problem here was loading time because there was a good bit of it, and Shang in particular was hurt. You could choose to have limited morphs (choose a few characters you want to morph into) or have a pause in the game every time you try to morph.
UMK3:
I don't remember the arcade having any fatalities the home systems didn't. The Genesis and SNES versions of the game had more characters overall then the Arcade did, and if anything they have more fatalities then the arcade did. However, both SNES and Genesis did a pretty poor job on UMK3, so what you gain in characters and fatalities, you lose in overall gameplay quality.
MK4:
Had some very interesting musics. The sound effects seemed rather generic. The announcer's voice I felt was just annoying because it sounded like a wanna-be Shao Kahn that was just tweaked in a sound prog and thrown on there.
