Control. Control control. Also balance.
As you've probably read, there are some control issues. It's not that the controls are bad or lacking in fluidity, but rather that we have to do them with a keyboard. Keyboards do not lend themselves to certain fighting game staples. Quarter circles are reasonable, but Z motions... I don't believe I ever pulled one off on purpose. They were all accidental while trying to do quarter circles. Really, you need to make the game support a gamepad so that we at least have the option.
Also, and this may not be something you can fix as I don't know how direct a port of Pocket Fighter this is, but the characters are pretty unbalanced, specifically Sakura and Chun-Li. Their rush attacks, I believe the quarter circle back special, are just unfair. Sakura's isn't as bad since it doesn't last as long, but Chun-Li's takes about 1/5 health chip damage, and it cannot be jumped over, at least not by a person with normal human senses. I would consider a rescale of the damage for both of them because it isn't hard to get special charges.
It mostly needs a tune up, but the idea is workable.