SwanSong

They are in level 4...

But I can't get them. I have no idea what item I need to use or puzzle to break to continue.

I can get into these rooms:
.X[]
.X[]
.X[]
[][][]
.X[]

but in the left-most room there is a shutter I can't open, right-most two shutters I can't open, and top a couple of blocks that look like the kind that drop when you push a switch.

You need arrows for the left side. The right, try the boomerang on the walls. The top, did you try stabbing anything. The arrows are the right side at the very top.