Mortal Kombat 1 enhanced with extra graphics.
There is a full music video from the Mortal Kombat movie that you can watch whenever you start the game.
The graphics are enhanced over the regular Genesis version. The finishing moves are bloodier and the sound it a little better.
Load time from the CD for finishing moves are awful. Level loads are almost as bad.
The Bottom Line
Mortal Kombat was one of the video games at the center of the controversy that caused video game ratings (ESRB) to be added to all games. Mortal Kombat used digitized pictures of live people and actors. This made it stand out over Street Fighter, it's main rival in the arcade.
Nintendo caved in and removed all the fatalities and replaced them with "finishing" moves in the SNES version.
Sega hinted of a special "code" that changed the graphics of the Genesis version. Once you got this code the blood would flow. The SNES version was better graphically but the lack of gore takes away from the game.
The SegaCD version has better fatalities and did not need any codes. Blood flies everywhere. If you like the original Mortal Kombat then this CD is a must for any collector.