Ok how would I make it so that when you level up you get less exp from enemies? Like this: (joebob is me and fry is the enemy) Joebob kills fry then gets 50 exp and gains a level, then Joebob kills fry again and he gets 40 exp?

And my second question is how would I make it so that when I hold down ctrl instead of just keep attacking it makes a charge attack and plays an animation like blue sparks around your char