Add a flag that indicates whether or not a texture is within the bounds of the view port. If it is not, skip the draw call for that object.
This should significantly increase overall frame rate and reduce the load on the GPU.

No need to render something that cant be seen.

Any gameobject which contains a rigid-body must be able to collide with other rigid-bodies.
Also having the ability to disable motion physics on any given object will be useful.

Proposed changes:
flag CanCollide - If set to false, objects with canCollide turned on can pass through this object.
flag Anchored - if set to true, forces on the object will have no effect.

It may be worth adding a "Drift Mode" which in this case would be triggered by holding the Space Bar.
This would change W, A, S, and D to a more standardized movement pattern (for a brief, rechargeable, period of time) that only occurs while holding the spacebar.

I feel like this could assist players with some fine tuned movement when they are trying to line up their attacks.

All assets shall be bound to a global scale such that the game play will not change when the screen size changes.

The camera system shall focus on the fish, leaving the fish in the center at all times. I think some rubber banding would be nice and could make the camera movement feel more natural.

We will need a game object to represent a full screen background which subtly moves as the player moves (for an effect of depth).

This feature is to define the specs for the fish control system.

Given that the current platform for the game is PC, we will need both controller support and keyboard support to support the largest number of users.

Proposed default keyboard controls:
W to swim forward.
S to swim backwards.
A & D to rotate the character.
E to equip or interact with game objects.
Hold Left Shift to dash.

Proposed default controller controls.
Horizontal Axis on Left Thumb-stick for movement.
Vertical Axis on Left Thumb-stick for rotation.
R2 Bumper to dash.
R1 Bumper to equip and interact.

See #1 for a potential enhancement to this system