And how is it going?

[Elmascapo777]

Was it possible to add new characters? Modify movements and animations?
Has anyone finally "fixed" the game, I mean a version that matches the arcade version?
Greetings kombatants.

[Gambid]

Add characters, not really. The only thing possible, as far as I know, is creating skins for existing characters.
Same goes for moves and animations.

Don't really know what you mean by "fixed" the game. MK4 for PC is what it is. Patches fixed a lot of things, but if you are looking for graphics close to the Arcade that is simply not possible with I guess rewriting the engine. It is also not a game based on a familiar engine, so that is a problem on its own.