Too easy...
As the others mentioned, constantly mashing "S" won't let the enemy have a chance to hit you. I would recommend adding super armor armor to enemies, at least they won't stagger when hit. Another point is that this game has the same probs as DMC, like what to do with those extra points after upgrading and buying everything. The level restart codes do work, however you don't get all your equips, just a measly 1000 points. I had to restart the last boss fight with the default weapons, since I killed the boss till he had negative HP, which kinda glitched the game. But I would like to say this game is pretty fun, but needs more work, try adding more natural ninja based projectiles and once again thanks for this game you've made.