Well done on making a game!
I really liked the story and the opening scene was very well put together. However, the character felt "heavy" (if that makes sense). Also, the controls were difficult to use; I'd consider reallocating the keys.
The amount of content you put into this game in a short period of time is really impressive. I really enjoyed how the cave got darker the further you went through. I felt that the monsters were very hard to avoid. The biggest difficulty I had with the game is that I ran out off o2 and the player just laid there (I closed the game after that because i didn't know how to continue).
With all that being said, overall the game is very impressive and with a bit more time spent on it I think it could be awesome!