shock is way too op, I kept not getting any runs on any difficulty without it past floor 5. it one shots ALL CAT GIRLS (some of the most annoying enemies) and stuns for 4 TURNS, it negates any kind of difficulty you might have without it. the cooldown is negligible as well, it refreshes one turn after the enemy is unstunned. If you want to win, get shock.
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.