Good point, there's definitely some balancing to do. It used to have a long cooldown but an early IRL play-tester complained. I think I'll bring back the cooldown, or at least make it more expensive in mana. And it probably doesn't need to stun for so long.
I don't actually mind it being so powerful. I like the idea that in the early game, we are weak prey, while in the late game, we are an unstoppable menace. I would recommend, adding more upgrade levels. So, abilities start very weak but once you upgrade one ability 4-5 times, it can dish out some insane damage (though I don't mind the cooldown, let's not get too overpowered too quickly). So, once you have 2-3 abilities maxed out, you just waltz through every enemy the game throws at you.