-- We simulate gravity by decrease the velocity slightly on each frame, corresponding to a downward acceleration.
--
-- We bounce of the bottom edge by reverting the velocity (with a damping factor).
--
applyGravity _now _time (World (x, y) v anim keys) = 
  World (x, y) (if y <= (-200) + slimeHeight / 2 then v * (-0.5) else v - 0.5) anim keys
applyGravity _now _time (World (x, y) v anim keys) = 
  World (x, y) (if y <= (-200) + slimeHeight / 2 then v * (-0.5) else v - 0.5) anim keys
applyGravity _now _time (World (x, y) v anim keys) = 
  World (x, y) (if y <= (-200) + slimeHeight / 2 then v * (-0.5) else v - 0.5) anim keys