I'm not thinking to much but maybe a sum wot leveling system like the shark gets stronger the more times that you kill it anther cool little feature would be that storms and the way to stay safe is to have a bunker get this under water it will be a nice little touch to add to the games difficulty not just that but new buildings like tubes and gear like a harpoon gun which can only be used under water and their can be that you need glass can be added in the game and under water their can be a like sunken boat with supplies and a note which can say sum think that will start you on a little journey the fine land again but at the end of the hole journey a plot twist ant their is no ending haha so i'm interestint in what you have to say about my ides.