NOT WORTH THE TIME.
However, it appears that the nostalgic desire for "olde school" games has kept desire for this title alive.
I am not against Ultimate MK3 entirely. I loved this game long ago (back in 1995) when MK3 was on SNES and the newly released Playstation. What I did perfer however was the remake of this game into Mortal Kombat Trilogy - which featured ALL of the MK characters up until that point in time. TRILOGY is what should have been ported to the Xbox360 (or even the original Mortal Kombat), rather than this version with its incomplete character list. Even if I ignore the lack of characters, what completely escapes me is how this game could play this sloppily on the state of the art 360. The graphics are slow and choppy and actually manages to look worse on 360 that it did on SNES. This port of the game pales in comparison to TRILOGY on the Playstation.
Also lacking is the control. UMK3 was released way back in the days of SNES - way before controllers had "dual shock analoge" or 8-way D-pads. The control on this version is HORRIBLE. I found it nearly impossible to pull off my character's signature moves without my fingers slipping to hit the Xbox ring of light button in the top of the controller or the "back" button.
Add to all this dissapointment the fact you must use gamer points to actually get the full version of this game which is not worth playing on this system, and you might as way stay away from it. Just go out and get ARMAGEDDON on 360 and you'll have access to over 4 dozen characters with great graphics and full control.