I got to try out the trainer finally, I have a few things to note below along with some screenshots.
1) You can enable the "Unplayables", you can get unlimited health, one hit kills, lock the timer at 60 seconds. And you can also get max money for the Krypt and also the ability to unlock all locked krypts. Here is the options of the trainer.
<img src=http://www.trmk.org/images/mkd/hacked/untitled100.jpg>
2) None of the characters have special moves, except for Monster who is just another costume for Scorpion. So our hopes of having Cage, Kitana, Kung Lao, or even Onaga are wearing thin if the characters don't have any built in special moves in the game. This is not a side-effect of the hacking because Monster has moves and moves lists, none of the other characters do. Just two fighting styles and a weapon (or three Dragon Styles if you are Onaga). All the moves are generic like "Special Moves Name" and "Style Two Attack One". See examples below:
<img src=http://www.trmk.org/images/mkd/hacked/untitled100.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled101.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled102.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled103.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled113.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled114.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled116.jpg>
2) If you play as Onaga and let the computer defeat you, it goes into his death animation. But no game ending, it asks you to continue. You can see it here:
<img src=http://www.trmk.org/images/mkd/hacked/untitled104.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled105.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled106.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled107.jpg>
The characters able to be played as are as follows: Monster, Onaga, Jax, Old Raiden, Quan Chi, Kung Lao, Cage, Sonya, Nitara, Shang Tsung, Frost, Kitana and Drahmin. I have included a few of those characters here.
<img src=http://www.trmk.org/images/mkd/hacked/untitled108.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled110.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled111.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled112.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled115.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled117.jpg>
<img src=http://www.trmk.org/images/mkd/hacked/untitled118.jpg>
NOTE: The pictures may look funny (squished) because they are taken from a 16x9 mode of MKD. And also due to movement some of the characters look blurry, this has to do with interlaced television signals, I don't have a HDTV card for my PC or I'd provide some very sweet looking HDTV progressive scan hi-def photos from MKD.