Glad you liked it!
As I had to keep co-op in mind from the very start, I couldn't delegate aiming to the mouse as I had originally intended(Most people don't have two mouses for player 2!), so I opted to have the aim point where you're moving. However the submarine side-to-side animation looked a little funky, so I inverted it. I didn't really think about how this affected the aim at the time so it's certainly more challenging than I originally anticipated. In the future I'll be sure to spend more time in making sure these things are more well planned.