Thank you, guys!
Yes, for the most part this is an illustration but in the pixel art format. I don't usually take the time to do preparation as most of my pieces are either a short daily piece or part of a bigger project and most pre-production material is prepared before hand.
Since I had made a sea scene image with a giant octopus and that was very popular, I decided to do another sea scene but record the process for posterity and to share.