story, lore, enemy types, bosses, trap types, enemy attack effect ideas, character style, ideas for character creation, pets, character random traits (blindness, forgetfulness, and stuff like that will actually affect game-play), special items(will affect player progression), Easter-eggs, jokes, anything even down to the font style :) the only thing that I limit you guys to is that it's 2D(which you know), it's going to have a dungeon/castle feel to it, turquoise and violet will be the main color accents, and that my team it programming, producing, and publishing it :)