diff --git a/src/App.vue b/src/App.vue
index 2458dd9..c789549 100644
--- a/src/App.vue
+++ b/src/App.vue
@@ -19,7 +19,9 @@ export default {
 
 <style>
 html,body,#app {
-  display: block;
+  display: flex;
+  flex-flow: column nowrap;
+  justify-content: center;
   width: 100vw;
   height: 100vh;
   background: black;
@@ -27,5 +29,4 @@ html,body,#app {
   padding: 0;
   overflow: hidden;
 }
-
 </style>
diff --git a/src/Background.vue b/src/Background.vue
index f20cdab..149ece6 100644
--- a/src/Background.vue
+++ b/src/Background.vue
@@ -4,6 +4,7 @@
 
 <script>
 import solarQuartet from './solar-quartet'
+import { BLOCK_SIZE, STAGE_WIDTH, STAGE_HEIGHT } from './level/def'
 
 export default {
   name: 'background',
@@ -21,18 +22,16 @@ export default {
     time () { this.refresh() }
   },
   mounted () {
-    const canvasSize = 512
-    const godraysSize = 128
     const canvas = this.$refs.canvas
     const godraysCanvas = document.createElement('canvas')
-    canvas.width = canvasSize
-    canvas.height = canvasSize
-    godraysCanvas.width = godraysSize
-    godraysCanvas.height = godraysSize
+    canvas.width = STAGE_WIDTH * BLOCK_SIZE
+    canvas.height = STAGE_HEIGHT * BLOCK_SIZE
+    godraysCanvas.width = ~~(canvas.width / 8.0)
+    godraysCanvas.height = ~~(canvas.height / 8.0)
     this.redraw = solarQuartet.bind(
       null,
-      canvas, canvas.getContext('2d'), canvasSize, canvasSize,
-      godraysCanvas, godraysCanvas.getContext('2d'), godraysSize, godraysSize,
+      canvas, canvas.getContext('2d'), ~~(canvas.width / 2.0), ~~(canvas.height / 2.0),
+      godraysCanvas, godraysCanvas.getContext('2d'), godraysCanvas.width, godraysCanvas.height,
     )
     this.refresh()
   },
@@ -65,8 +64,8 @@ export default {
 <style>
 #background {
   display: block;
-  width: 100%;
-  height: 100%;
+  width: var(--field-width);
+  height: var(--field-height);
   object-fit: contain;
   background: black;
 }
diff --git a/src/Field.vue b/src/Field.vue
index 8723438..592027d 100644
--- a/src/Field.vue
+++ b/src/Field.vue
@@ -1,13 +1,14 @@
 <template>
   <div id="field" :class="daytimeClass">
     <input v-keep-focussed type="text"
-      @keydown.up="jump = jump || !blocked.down ? jump : 20"
-      @keydown.down="moveTo = 'down'"
-      @keydown.right="moveTo = 'right'"
-      @keydown.left="moveTo = 'left'"
-      @keyup.down="moveTo = null"
-      @keyup.right="moveTo = null"
-      @keyup.left="moveTo = null"
+      @keydown.up="inputY = -1"
+      @keydown.down="inputY = 1"
+      @keydown.right="inputX = -1"
+      @keydown.left="inputX = 1"
+      @keyup.up="inputY = inputY === -1 ? 0 : 1"
+      @keyup.down="inputY = inputY === 1 ? 0 : 1"
+      @keyup.right="inputX = inputX === -1 ? 0 : 1"
+      @keyup.left="inputX = inputX === 1 ? 0: -1"
       @keypress.p="togglePause"
       @keydown.space="digging = true"
       @keyup.space="digging = false"
@@ -18,7 +19,7 @@
         <div v-for="(block, x) in row" class="block" :class="[block.type]" />
       </template>
     </div>
-    <div id="player" :class="[playerDirection]" />
+    <div id="player" :class="[player.direction]" />
     <div id="level-indicator">
       x:{{ floorX }}, y:{{ floorY }}
       <template v-if="moving !== false">({{clock}})</template>
@@ -29,36 +30,39 @@
 
 <script>
 // import throttle from 'lodash/throttle'
-import Level from './level'
 import MountainBackground from './Background'
+import Level from './level'
+import { Moveable } from './physics'
+import {
+  BLOCK_SIZE,
+  RECIPROCAL,
+  STAGE_WIDTH,
+  STAGE_HEIGHT,
+  PLAYER_X,
+  PLAYER_Y
+} from './level/def'
 
-const BLOCK_SIZE = 32
-const RECIPROCAL = 1 / BLOCK_SIZE
-const PLAYER_X = ~~(BLOCK_SIZE / 2) + 1
-const PLAYER_Y = BLOCK_SIZE - 15
-const PLAYER_MAX_VELOCITY = 32
-const level = new Level(BLOCK_SIZE + 2, BLOCK_SIZE + 2)
+const level = new Level(STAGE_WIDTH + 2, STAGE_HEIGHT + 2)
+const player = new Moveable(PLAYER_X, PLAYER_Y)
 
 export default {
   name: 'field',
   components: { MountainBackground },
   data () {
     return {
+      player,
       x: 0,
-      y: 0,
-      playerDirection: 'left',
-      playerVelocityX: 0,
-      playerVelocityY: 8,
-      moveTo: null,
-      jump: 0,
-      digging: false,
-      gravity: 8.0 / 20,
+      y: 12,
+      inputX: 0,
+      inputY: 0,
+      time: 250,
       moving: false,
-      time: 250
+      lastTick: 0
     }
   },
   mounted () {
-    this.move()
+    this.lastTick = performance.now()
+    this.move(this.lastTick)
   },
   computed: {
     rows () { return level.grid(this.floorX, this.floorY) },
@@ -110,28 +114,21 @@ export default {
     }
   },
   methods: {
-    move () {
+    move (thisTick) {
+      this.moving = requestAnimationFrame(this.move)
+
+      // keep roughly 20 fps
+      if (thisTick - this.lastTick < 50) return
+
       // set time of day in ticks
       this.time = (this.time + 0.1) % 1000
 
-      const x = this.x
-      const y = this.y
+      const player = this.player
+      const x = player.x
+      const y = player.y
 
-      if (this.moveTo !== null) this.playerDirection = this.moveTo
-
-      if (this.moveTo === 'right') {
-        this.playerVelocityX = 8
-      } else if (this.moveTo === 'left') {
-        this.playerVelocityX = -8
-      } else {
-        this.playerVelocityX = 0
-      }
-
-      // this.player_velocity_y += this.gravity
-      let dx = this.playerVelocityX * RECIPROCAL
-      let dy = (this.playerVelocityY - this.jump) * RECIPROCAL
-
-      if (this.jump > 0) this.jump -= 2
+      let dx = player.vx * player.dir * RECIPROCAL
+      let dy = player.vy * RECIPROCAL
 
       // don't walk / fall into blocks
       if (dx > 0 && this.blocked.right) dx = 0
@@ -140,14 +137,14 @@ export default {
       if (dy < 0 && this.blocked.up) dy = 0
 
       // don't walk, work!
-      if (!this.jump && this.digging) {
+      if (!this.inputY && this.digging) {
         dx = 0
         this.dig()
       }
 
       this.x += dx
       this.y += dy
-      this.moving = setTimeout(() => this.move(), 64) // roughly every 4 frames
+      this.lastTick = thisTick
     },
     dig () {
       console.log('dig', this.playerDirection, this.surroundings[this.playerDirection])
@@ -163,10 +160,9 @@ export default {
     },
     togglePause () {
       if (this.moving === false) { // is paused
-        this.moving = true // avoid (unlikely) race condition
         this.move()
       } else {
-        clearTimeout(this.moving)
+        cancelAnimationFrame(this.moving)
         this.moving = false
       }
     }
@@ -179,7 +175,7 @@ export default {
 :root {
   --block-size: 32px;
   --field-width: 1024px;
-  --field-height: 1024px;
+  --field-height: 576px;
   --spare-blocks: 2;
 }
 
diff --git a/src/level/def.js b/src/level/def.js
index 8e747fe..edf4778 100644
--- a/src/level/def.js
+++ b/src/level/def.js
@@ -1,3 +1,15 @@
+export const BLOCK_SIZE = 32 // each block is 32̨̣̌̇x32 pixel in size and equals 1m
+export const RECIPROCAL = 1 / BLOCK_SIZE
+
+export const STAGE_WIDTH = 32 // 32*32 = 1024 pixel wide stage
+export const STAGE_HEIGHT = ~~(STAGE_WIDTH * 0.5625) // 16:9 😎
+
+// the player position is fixed to the middle of the x axis
+export const PLAYER_X = ~~(STAGE_WIDTH / 2) + 1
+export const PLAYER_Y = ~~(STAGE_HEIGHT * 0.5) // fall from the center
+
+export const GRAVITY = 10 // blocks per second
+
 export const type = {
   air: {type: 'air', hp: Infinity, walkable: true},
   grass: {type: 'grass', hp: 1, walkable: false},
diff --git a/src/physics.js b/src/physics.js
new file mode 100644
index 0000000..53dbb2d
--- /dev/null
+++ b/src/physics.js
@@ -0,0 +1,22 @@
+import { GRAVITY } from './level/def'
+
+/** physics gets input like
+      instance of Moveable,
+      position: [x, y],
+      surroundings: [top, right, bottom, left] where each is a block type
+    and updates the Moveable instance values accordingly
+*/
+
+export class Moveable {
+  constructor (x, y, direction = 1) {
+    this.x = x
+    this.y = y
+    this.dir = direction
+    this.vx = 0
+    this.vy = 0
+  }
+
+  get direction () {
+    return this.dir > 0 ? 'left' : 'right'
+  }
+}