That's pretty good, if you ask me.
I like it. I like it a lot. A couple of bugs:
1) When you're fighting against a dark background, you can't see the oponent's health. You can see the red bar, but you can't read the numbers.
2) When you finally buy the final armor, the "sale" button doesn't go away. You wear it, but the name doesn't appear.
3) I beat it under "advanced", and got the code, but it didn't work (unless I'm putting it in the wrong place).
4) Sometimes your health drops into the negatives. Usually when you use a skill at the same time as being hit.
And a few things I would recommend to be added (not saying this to be mean- it's already much better than anything I could do; I'm just trying to help you out):
1) If you're going to use the number pad for skills, why not also use it for attacks? "0" could very easily be used. If you don't want to use the number pad, then don't make the "Attack" button disapear between turns. Just phase it out a bit. If you accidentally move your mouse, it'll take you a couple seconds to realise why you're not attacking.
2) Same thing with the skills- don't make them dissapear, just make them transparent or grey them out or something. I occasionally forgot which #button was which skill, and I would end up hitting th ewrong one.
3) You definitely need to have something happen between battles. Like having your home (or whatever the place is where you walk around) change between levels.
4) Add more story elements. Nothing much, just maye a person or 2 to talk to, and have the dialogue change each level.