Ok, just to start off with this is a great idea game, lots of running games are overcomplicated and throw too much at you to respond and this one throws that out the door, really good simple controls, good character variations, great upgrade system and really good looking pixel art (my favourite is the knight).
But just as people below and surly above will say, the controls are broken, it's not clear at what time you should swing your weapon and when it will hit your enemy, you cannot change your character at will, the run button makes you swing your sword and is too short making it useless and platforms need to be more solid and apparent in where you can land.
If there is ever an update or a sequel try to patch these problems because it can become a really good game, but ultimately the mechanics are flawed.