The Basic Idea is good, but there is a lot, that needs to be polished. It's easy to fall of the narrow diagonal platforms with the keyboard, because you have to press two keys at the exact same time to walk diagonally. Drawing a circle also feels a bit tricky, maybe because you have to hit the exact starting point. Either the speed of mana regeneration or the maximum mana should be increased, as you spend too many seconds waiting to do the next attack.