Yes I know half a day has already passed but, I finally have an idea I'm willing to work on.

Not even the dreaded man-flu will stop me from participating! (it will probably stop me from finishing a game but hey its not like my idea is viable for a 3 day jam anyway!)

If you still don't have a good idea for LD40 I want to give you my number 2 and 3, feel free to use them if you like them:

Game Idea #2: Bar-Fight

Top-Down beat'em up, Hotline Miami style, but most of the patrons are neutral just enjoying their drinks, you start fighting, bump into patrons, they drop their drinks get angry join the fight, hence the theme: the more enemies have you got the worse it is. Maybe add the ability to hurl furniture at each other, and friendly fighters if the enemy bumps into an neutral patron. I could do this but I don't really like beat'em ups.

Game Idea #3: Crazy cat lady

Game screen is an apartment, your character adopts a cat at a fixed pace, you need to care for the cats or they will get frustrated and more dangerous, and maybe die, (like food, drink, pick up poop, play). If your cats are frustrated it's more likely they will do something stupid, like knock a standing lamp over and set the couch on fire, eventually they will burn down your apartment or destroy it some other way, the objective is to see how much cat you can own before they destroy your house, like with leader-boards or something. Bonus points: make the game anime style call it Neko Musume or something like that. The problem is you will have to make a lot of animation of cats, sou you need to be a capable artist to do this in time, I couldn't do this in time.