Oh sorry to hear that! It's quite unusual that a WebGL game can crash the whole PC, worst case is normally just the browser... anyhow at least I am not sure what the cause might be since I didn't see or hear of that bug before.
Regarding the attack: YES you hit in the direction you look at, or at least you hit left or right depending on whichs characters side your cursor is at. And yea maybe the "got hit" animation should be more obvious so that you notice when you got hit, I thought a sound and a small flicker animation is enough, but maybe its to subtle
Yea energize is that glowing sword you can see in the images / trailer which you are able to activate when those "green arrow" thingies at the top left are full.
Nonetheless thank you very much for your positive feedback :)