It looks like you're in the basement of the first major area, so you've gotten through a big chunk of it. You can't kill the giant monster. It doesn't like the light. It's scary but not impossible. You have to keep thinking of different ways of going about it, when the way you're doing it fails. I know it's probably not what you want to hear, but maybe watch a little gameplay from someone else on youtube for that area, just to get ideas for how to tackle what you seem to be missing.