I've been working on a huge mugen project with about 6 other guys for a long time now. Hardly any of them speak English so any work I do is pretty much through Konqrr programming it and me explaining it. Our main goal is to get all the basic gameplay aspects working 100% and then move onto special moves which some need special attention. As a test we programmed in a new move (with a couple hacked sprites) for Sheeva. It is a Sumo Stomp that will open some juggling opportunities for her.
http://www.darktemplarz.com/tempmatt/sheevastomp.wmv
The stomp is missing it's recovery frames in this video, but she will not instantly go back into her stance when we add them. Every now and then we work on it and get something working pretty well. Overall the game's %'s in terms of these aspects are the following:
Sprites: 99% - There are still some sprites we have to custom make for everyone, like MKII Kung Lao's hat split...etc
Sounds, Music: 85% - every sound and music from MK will eventually be in the game, even MKDA and MKD to add to variety. Probably every character will have their own voice and every stage will have it's own music.
Backgrounds: over 100% - there are so many brand new stages.
Fatalities: Most still need to be preserved, all characters will do their original fatalities and have a ton of new ones. MKII characters, when doing their fatalities will have the reaction of MKII, so if you decapitate Kabal with MKII Johnny Cage, his head will flip off, bounce, roll, and the body will drop to his knees and fall forward, if you decapitate MKII Johnny Cage with Ermac, his head will cut off and the body will stay like UMK3. This will be all for variety's sake.
Gameplay: 5% - The people who started making this game focused on mass producing the characters just to get them into a playable environment, but since Konqrr and I joined their team we have been fine tuning it so it'll eventually play exactly like UMK3. After that we'll tweak all the characters, power up some, balance others. All the original combos will be preserved except for the hack job combo charactersin MKT. They will all have new combos with a lot of variety, for instance, special move animations like projectiles that look like normal attacks will be hacked in as moves in combos, without the projectile coming out, or some moves that just make sense to finish a combo, like Raiden's Superman in MKT. A few new combos and moves will be added here and there as well. We understand the system of game so well that the only thing you'll be able to tell the difference between this and a real arcade game is the size of the screen, since it can only be 320X240 right now (stretchable) the characters will look a lot bigger full screen. Once we get all the basic gameplay elements working for one character, and collision boxes for one character, we can apply all of it to every other character, and the gameplay % will jump to about 50%. After that we'll go through and modify the collisions to get them right for everyone, and some of the normals have slightly different properties.
We are focusing on Scorpion right now, making all of his attacks and collision boxes work correctly. Sheeva is using a different command set than Scorpion right now so she is kinda slow, as you can see with her punches, and they don't work right. That Reiko is a sprite edit of Sub-zero, a very good one at that. Almost the entire cast of MKT PSX is in the game right now and eventually every version of every character from 2D MK will be as well, and any Reiko quality sprite edits will be in it as well for whatever characters people make.