Decent game, but it has a lot of issues.
The "Firearms Collector" medal is broken. It only works in-game, not on NG.
Most items and moves are redundant. Lightning orb is overpowered. Lightning orb cost should be 5.000-8.000 or even 10.000. The last boss can be stun-locked by lightning orb, and it does 30 damage to him each time you use it.
Launching slash is overpowered as well. Holding space gives you endless combos, the opponent never lands. Since 20hit combo (Killer Combo) is the limit for Ki points, there's no point in going any further unless you want to be a high-score whore.
The controls are sketchy and combos don't always launch. A game that caters to combos and keyboard mashing, but then stops combos when you do so is a bit weird. Many more combos would've been welcome, perhaps an extra attack, equivalent to the S key to make it happen. Arrow keys + A S D would've been a better layout.
The opponents are reacting too slow. Even with the controls as they are, the opponents hesitate too long before attacking. I doubt that you'll address the problems I mentioned, but if you decide to fix the controls to make them more fluent, and add some movement instead of static attacks only, then the computer reflexes should be even better than just a little improved.
The music got repetitive. Compressing the music a bit more and adding 1-2 or more extra sound tracks would've been welcome
The idea of needing certain moves to proceed is cool, the way it is executed is not. Having a move for the sake of having it is pointless. if you had made some opponents that for an example couldn't be hurt unless you power-attack. Or aerial drones that fire upon you from above which makes it impossible to win without the aerial combos, it would've been cool.
Progression besides that was cool. You felt the enemies you meet at earlier levels become weaker compared to you and the later enemies.
As you can see I haven't given you that bad a score in spite of these issues. The reason is simple, I enjoyed the game. That has a lot of value!
With the things I mentioned in order, if you should decide to make a sequel, this would be a solid 5!