Thanks for the useful feedback. I feel the game is polished in some ways, but with so little time, it's of course very rough in others.
If you divide the pilar in a 2x3 sections, the bottom 4 are the actual collision shape, so they block the vision. In that case, the vision cone should be working well, but they have rounded corners, which I added in the last day to fix navigation, so I didn't check how those are affecting it, maybe it's breaking it. What's not working so well is around some corners of the walls, because if you are in a corner just below the room, what you see as a corner is the top of the wall, not the bottom, which means some rays seem to be going through the corner of the wall.
The second level was designed more carefully. However, I had forgotten about the spikes so I just added them 5 minutes before submission... I guess I was careless with them. Sorry about that.
Thanks for the feedback. I'll surely apply it when I expand the game.