PICO-8 Example
player = {}

function _init()
  cls()
  player.x = 60
  player.y = 60
  player.speed = 2
  player.sprite = 0
end

function _update()
  cls()
  player.moving = false
 
  if btn(0) then 
    player.x -= player.speed 
    move() 
  end
  if btn(1) then 
    player.x += player.speed 
    move()
  end
  if btn(2) then 
    player.y -= player.speed
    move()
  end
  if btn(3) then 
    player.y += player.speed
    move() 
  end
 
  if (player.moving == false) player.sprite = 0 
end

function _draw()
  rect(0,0,127,127,11)
  rectfill(5,10,122,40,2)
  print ("press z to fart",32,90,5)
  spr(player.sprite,player.x,player.y)
  print ("press z to fart",33,89,7)
end

function move()
  player.moving = true
  player.sprite += 1
  
  if (player.sprite > 2) player.sprite = 0
end