This is a really neat game. I would agree that a little more intro would help, but it's definitely surmountable and fun. The music made me feel like calm underwater, which contrasted with "Hungry!" hahaha. The first time, I didn't realize it was kinda like Lufia 2, where the enemy only moves when you do, so I booked down a corridor to my death xD, but just once.
Once that's established, the puzzle style became clear. One thing I think might improve it even more is if the difficulty was not partially the need to know the layout somewhat, and find that out by perishing first. However, I'm fine with the explanation that I'm not smart enough to do it right the first time LOL.
Nice work!