I plan to add bigger and potentially more intense obstacles. More upgrades. More player features. some easy things to add would cut the 999 air time upgrade into chunks of like 33 and have an upgrade to allow further upgrades. You know more things for longer game, filler stuff. I want to add enemies such as fish and crabs and sharks. I want to go through and rework all the art. And so much more. I actually have a thought chain I can build off of and I'm so thankful of this Jam for the theme. Sometimes just a push, in one direction can set, the whole path.
Also I left a comment about your game it was very intriguing slightly aggravating but overall fun. Very almost skill heavy, no? Maybe I should work on my gaming skills than hey?