I'm working on an endless-runner-game type game where the player has to catch coins and avoid bombs. It's underwater in the ocean and the scrolling direction is downward. The player moves towards the ocean floor, except it's like an endless pit and he will never actually reach the ocean floor.The problem is that I don't know what to display as a background, because in open water there are no plants or rocks. With a horizontally scrolling game this is easier because you can show plants or the floor moving. The enemies slowly move upward ofcourse, but I don't think that's enough to convey the downward scrolling motion...Any tips or ideas will be much appreciated. Or does anyone know any underwater vertically games like this that I can take a look at?
I would put things like fish, cliffs, etc in background.