It took me a few minutes to realize what was happening (it's been a while since I've played a game like this), but once I did, it was fun figuring out how to best approach a given scenario. I played through about 15 rooms, and none of them felt insurmountable.
I'm not sure what your plans are for the colors, but if you keep the red and blue, I think the purple (that is, where the attack ranges overlap) doesn't contrast enough with the black background, so it was sometimes hard for me to tell whether I was safe from being attacked if I moved.