First of all, I like the darkness of the theme. There were quite a few bugs though.

First of all, you can use the flashlight in the hole before the hole is revealed. When I first did this, I assumed it was referring to the keyhole in the door, and so I was confused when I eventually uncovered the hole and got the same response.

If you don't answer 'yes' or 'no' when washing at the lake but just type 'clean', then it makes you go through the 'yes' or 'no' process when you try examining the lake again.

As Rich says, you always get the additional message of '...nothing happened' when outside the cave. This happens when you examine or get the rock (which it allows you to do), but also when you try to leave (which it doesn't allow you to do), meaning you're stuck if you haven't already got the fish.

Typing 'get apple' at the top of the tree gives both the 'you take' and 'you already took' messages.

Are you still meant to be carrying the neon fish after you've placed it on the pedestal?

After you've got the key for the chest, 'unlock chest' and 'use key' don't work, only 'open chest'.

Great ending though, really spooky.

Not sure if the engine is configured correctly, but a lot of objects aren't shown. You have to type 'objects' to see them. Also, I think I managed to see the key which I had gotten 'from in the safe' before I'd opened the safe (found one set of numbers but didn't actually find the other two). Like the idea, especially it's weirdness, but the game also seemed to crash to the east of the fish, it kept saying '...nothing happens' once the room description and added text was displayed. Would definitely play it again if it's fixed.