This was a great game.
The mirror element to me was perfect, I kept hiding and plotting (which was the intention behind it I'm sure lol) trying to figure out how to get pass this creature. I did notice a few times the creature would get stuck by the boat and I had no choice but to get killed so the creature could spawn somewhere else.
I would like to suggest adding a story with the creature that maybe you have to uncover in the full game. Like maybe someone summed it to cover up a mystery in the harbor or maybe a tainted spirit or tortured soul trapped here due to something terrible or a twist of some sort. Another suggestion maybe adding an element to the game involving the mirror such as having to travel in the mirror world to solve a puzzle to get past a certain point in the real world. Maybe making it a timed thing because the portal is open maybe other creatures can escape... Just a suggestion but either way I am a huge supporter of this project and I a sure it will great in the end! Keep up the great work.