Pretty fun game - nothing groundbreaking but the core works; very cool soundtrack. Two small "butts":
1. The diver's forward direction is not very intuitive because of how sprite posed. Most of the time it's not a problem, but in the heat of the moment can become one.
2. These pufferfishes are just blending with the environment completely, I dont' know how. Especially on the side stripes. When I focus on them they are clear, but when I look at the whole screen - they are almsot invisible. Maybe it's just me.
EDIT: grammar.