I think need to add some interesting themes for jam like : Horror, Roguelike, and more

No i prefer a
cooperation theme,
popular theme,
multiplayers theme,
communication theme, 
teams theme, 

survival theme,

fun theme,

war theme,

gun fps theme,

rpg theme,

Keep adding ideas, we might take them into account ;)

Retro, Shooter, Pixel Art based.

Story games (have lore and playing by 1 or 2 persons), games with a abilities/heroes what have abilities , realistic...

Too long

It's not as big as it seems

A button

game inside another game

break a leg