W and S are your up and down keys. A and D turn you. Space moves you. If you want to see more coral, move the slider up. If you use the max settings, turbowarp would be better in order to avoid lag. You can read words easier when the camera is under the waves.
Credits are hidden in-game. Sort of. Sometimes they appear in plain sight, and sometimes you must search. If one is ever blocking another, move around. You'll find another copy somewhere.