Just dodge lol

WASD, Space to dash, R to heal, hold LMB to charge up a shot, RMB for instant cast(if you have charges, each takes a few seconds to recover), E to interact. Z to make the UI follow the mouse(scuffed in web version), X+arrows to move the UI around the screen.

There's a few secrets, including a pretty big bossfight in the end - if you're sharp enough to find it.