Eh, 40 mins jam, while trying webaudio mic stuff, then stackgl particles... then panic...

rainbowsnake.js

document.title = "Blah"
var fit = require('canvas-fit')
  var canvas = document.body.appendChild(document.createElement('canvas'))
  window.addEventListener('resize', fit(canvas), false)
  var ctx = canvas.getContext('2d')

player = {}
  player.p = []
  player.p[0] = canvas.width/2
  player.p[1] = canvas.height/2

food = []

var keysDown = {}
document.addEventListener("keydown", function(e){
  keysDown[e.keyCode] = true
  e.preventDefault();
})
document.addEventListener('keyup', function(e){
  delete keysDown[e.keyCode]
})

update = function(s){
  if(keysDown[37]){ player.p[0] -= s }
  if(keysDown[38]){ player.p[1] -= s }
  if(keysDown[39]){ player.p[0] += s }
  if(keysDown[40]){ player.p[1] += s }
  // if(keysDown[32]){ player...?}
}

score = 0
count = 0
function render(){
  count++
  if(count > 10){
    food.push([Math.random()*canvas.width, Math.random()*canvas.height])
    count = 0
  }
  t = Date.now()
  osc = 5*Math.sin(t/400) + 2*Math.cos(t/400)
  update(5)
  ctx.fillStyle = "rgba(0,0,0,0.1)"
  ctx.fillRect(0,0,canvas.width,canvas.height)
  ctx.fillStyle = "hsla("+(180+180*Math.sin(t/100))+",100%,50%,1)"
  // ctx.fillRect(player.p[0] - osc/2, player.p[1] - osc/2, 10+osc,10+osc)
  ctx.fillRect(player.p[0] - osc/2 + 10*osc*Math.sin(t/150), player.p[1] - osc/2 + 10*osc*Math.sin(t/100), 4, 4)
  ctx.fillRect(player.p[0] - osc/2 + 10*osc*Math.cos(t/100), player.p[1] - osc/2 + 10*osc*Math.cos(t/150), 4, 4)
  ctx.fillRect(player.p[0] - osc/2 + 10*osc*Math.cos(t/200), player.p[1] - osc/2 + 10*osc*Math.cos(t/100), 4, 4)


  ctx.fillStyle = "hsla("+(180+180*Math.sin(t/600)*Math.cos(t/400))+",100%,50%,1)"

  foodTemp = []
  for(var i=0; i<food.length; i++){
    if( Math.abs(player.p[0] - food[i][0]) + Math.abs(player.p[1] - food[i][1]) > 75) {
      foodTemp.push(food[i])
    } else {
      score++
    }
  }
  food = foodTemp
  for(var i=0; i<food.length; i++){
    ctx.fillRect(food[i][0], food[i][1], 10, 10)
  }
  ctx.font="50px Verdana";
  ctx.fillText(score,50,50);
  window.requestAnimationFrame(render)
}
render()

Collisions were borked, forgot Math.abs a second time, should have fixed it before submitting, but eh.