Here's a game I made for an example for my class, This game has been worked on in bits!

Aim of the game: Avoid incoming missiles and upgrade your rocket (Don't laugh at the sprites xD)
How it works: Costume + Costume + Costume / Number = Speed, Costume + Costume + Costume / Number / 2 = Speed falling
Speed / 2 = Missile speed

Forever
if <key space> is pressed
move (speed) steps
wait 0.1
change {fuel} by (-1)
wait 0.1
end
end