I like the music track -- definitely captures the mood of the adventure, and the string pads evoke that underwater feeling.
It's also surprisingly satisfying to watch your photos scroll by, at the end of the game.
Gameplay-wise and theme -- I didn't feel I was underwater so much (maybe some visual post effect?) and I thought what if there was a little bit of a second area where you had to run /delve "deeper" to get to. I feel like I found a secret one behind the ship, but then realized I'd already photo'd him elsewhere :( It could also be fun to have some creatures that were harder to capture on film, although I missed the manta a bunch of times as-is. Overall great job!