diff --git a/common/Protocol.js b/common/Protocol.js
new file mode 100644
index 0000000..07f4ccb
--- /dev/null
+++ b/common/Protocol.js
@@ -0,0 +1,51 @@
+/*
+SERVER_CLIENT_MESSAGE_PROTOCOL
+NOTE: clients always send game id and their id
+      when creating sockets (via socket.protocol), so
+      this doesn't need to be set in each message data
+
+NOTE: first value in the array is always the type of event/message
+      when describing them below, the value each has is used
+      instead of writing EVENT_TYPE or something ismilar
+
+
+EV_CLIENT_EVENT: event triggered by clients and sent to server
+[
+  EV_CLIENT_EVENT, // constant value, type of event
+  CLIENT_SEQ, // sequence number sent by client.
+  EV_DATA, // (eg. mouse input info)
+]
+
+EV_SERVER_EVENT: event sent to clients after recieving a client
+                 event and processing it
+[
+  EV_SERVER_EVENT, // constant value, type of event
+  CLIENT_ID, // user who sent the client event
+  CLIENT_SEQ, // sequence number of the client event msg
+  CHANGES_TRIGGERED_BY_CLIENT_EVENT,
+]
+
+EV_CLIENT_INIT: event sent by client to enter a game
+[
+  EV_CLIENT_INIT, // constant value, type of event
+]
+
+EV_SERVER_INIT: event sent to one client after that client
+                connects to a game
+[
+  EV_SERVER_INIT, // constant value, type of event
+  GAME, // complete game instance required by
+        // client to build client side of the game
+]
+*/
+const EV_SERVER_EVENT = 1
+const EV_SERVER_INIT = 4
+const EV_CLIENT_EVENT = 2
+const EV_CLIENT_INIT = 3
+
+export default {
+  EV_SERVER_EVENT,
+  EV_SERVER_INIT,
+  EV_CLIENT_EVENT,
+  EV_CLIENT_INIT,
+}
diff --git a/game/Camera.js b/game/Camera.js
index 0f32c2a..bb92a67 100644
--- a/game/Camera.js
+++ b/game/Camera.js
@@ -35,6 +35,7 @@ export default class Camera {
       }
 
       // centered zoom
+      // TODO: mouse-centered-zoom
       this.x -= Math.round(((this.width / this.zoom) - (this.width / zoom)) / 2)
       this.y -= Math.round(((this.height / this.zoom) - (this.height / zoom)) / 2)
 
diff --git a/game/Communication.js b/game/Communication.js
index 04cdf8d..9a91573 100644
--- a/game/Communication.js
+++ b/game/Communication.js
@@ -1,41 +1,50 @@
 import WsClient from './WsClient.js'
+import Protocol from './../common/Protocol.js'
 
-const EV_SERVER_STATE_CHANGED = 1
-const EV_SERVER_INIT = 4
-const EV_CLIENT_MOUSE = 2
-const EV_CLIENT_INIT = 3
-
+/** @type WsClient */
 let conn
 let changesCallback = () => {}
 
-function onChanges(callback) {
+function onServerChange(callback) {
   changesCallback = callback
 }
 
+function send(message) {
+  conn.send(JSON.stringify(message))
+}
+
+let clientSeq
+let events
 function connect(gameId, playerId) {
+  clientSeq = 0
+  events = {}
   conn = new WsClient(WS_ADDRESS, playerId + '|' + gameId)
   return new Promise(r => {
     conn.connect()
-    conn.send(JSON.stringify([EV_CLIENT_INIT]))
+    send([Protocol.EV_CLIENT_INIT])
     conn.onSocket('message', async ({ data }) => {
-      const [type, typeData] = JSON.parse(data)
-      if (type === EV_SERVER_INIT) {
-        const game = typeData
+      const msg = JSON.parse(data)
+      const msgType = msg[0]
+      if (msgType === Protocol.EV_SERVER_INIT) {
+        const game = msg[1]
         r(game)
-      } else if (type === EV_SERVER_STATE_CHANGED) {
-        const changes = typeData
-        changesCallback(changes)
+      } else if (msgType === Protocol.EV_SERVER_EVENT) {
+        changesCallback(msg)
       }
     })
   })
 }
 
-function addMouse(mouse) {
-    conn.send(JSON.stringify([EV_CLIENT_MOUSE, mouse]))
+function sendClientEvent(mouse) {
+  // when sending event, increase number of sent events
+  // and add the event locally
+  clientSeq++;
+  events[clientSeq] = mouse
+  send([Protocol.EV_CLIENT_EVENT, clientSeq, events[clientSeq]])
 }
 
 export default {
   connect,
-  onChanges,
-  addMouse,
+  onServerChange,
+  sendClientEvent,
 }
diff --git a/game/EventAdapter.js b/game/EventAdapter.js
deleted file mode 100644
index 806959b..0000000
--- a/game/EventAdapter.js
+++ /dev/null
@@ -1,38 +0,0 @@
-export default class EventAdapter {
-    constructor(canvas) {
-        this._mouseEvts = []
-        canvas.addEventListener('mousedown', this._mouseDown.bind(this))
-        canvas.addEventListener('mouseup', this._mouseUp.bind(this))
-        canvas.addEventListener('mousemove', this._mouseMove.bind(this))
-        canvas.addEventListener('wheel', this._wheel.bind(this))
-    }
-
-    consumeAll() {
-        if (this._mouseEvts.length === 0) {
-            return []
-        }
-        const all = this._mouseEvts.slice()
-        this._mouseEvts = []
-        return all
-    }
-
-    _mouseDown(e) {
-        if (e.button === 0) {
-            this._mouseEvts.push({type: 'down', x: e.offsetX, y: e.offsetY})
-        }
-    }
-
-    _mouseUp(e) {
-        if (e.button === 0) {
-            this._mouseEvts.push({type: 'up', x: e.offsetX, y: e.offsetY})
-        }
-    }
-
-    _mouseMove(e) {
-        this._mouseEvts.push({type: 'move', x: e.offsetX, y: e.offsetY})
-    }
-
-    _wheel(e) {
-        this._mouseEvts.push({type: 'wheel', deltaY: e.deltaY, x: e.offsetX, y: e.offsetY})
-    }
-}
diff --git a/game/PuzzleGraphics.js b/game/PuzzleGraphics.js
new file mode 100644
index 0000000..29dc7a7
--- /dev/null
+++ b/game/PuzzleGraphics.js
@@ -0,0 +1,119 @@
+import Geometry from '../common/Geometry.js'
+import Graphics from './Graphics.js'
+
+async function createPuzzleTileBitmaps(img, tiles, info) {
+  var tileSize = info.tileSize
+  var tileMarginWidth = info.tileMarginWidth
+  var tileDrawSize = info.tileDrawSize
+  var tileRatio = tileSize / 100.0
+
+  var curvyCoords = [
+    0, 0, 40, 15, 37, 5,
+    37, 5, 40, 0, 38, -5,
+    38, -5, 20, -20, 50, -20,
+    50, -20, 80, -20, 62, -5,
+    62, -5, 60, 0, 63, 5,
+    63, 5, 65, 15, 100, 0
+  ];
+
+  const bitmaps = new Array(tiles.length)
+
+  const paths = {}
+  function pathForShape(shape) {
+    const key = `${shape.top}${shape.right}${shape.left}${shape.bottom}`
+    if (paths[key]) {
+      return paths[key]
+    }
+
+    const path = new Path2D()
+    const topLeftEdge = { x: tileMarginWidth, y: tileMarginWidth }
+    path.moveTo(topLeftEdge.x, topLeftEdge.y)
+    for (let i = 0; i < curvyCoords.length / 6; i++) {
+      const p1 = Geometry.pointAdd(topLeftEdge, { x: curvyCoords[i * 6 + 0] * tileRatio, y: shape.top * curvyCoords[i * 6 + 1] * tileRatio })
+      const p2 = Geometry.pointAdd(topLeftEdge, { x: curvyCoords[i * 6 + 2] * tileRatio, y: shape.top * curvyCoords[i * 6 + 3] * tileRatio })
+      const p3 = Geometry.pointAdd(topLeftEdge, { x: curvyCoords[i * 6 + 4] * tileRatio, y: shape.top * curvyCoords[i * 6 + 5] * tileRatio })
+      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
+    }
+    const topRightEdge = Geometry.pointAdd(topLeftEdge, { x: tileSize, y: 0 })
+    for (let i = 0; i < curvyCoords.length / 6; i++) {
+      const p1 = Geometry.pointAdd(topRightEdge, { x: -shape.right * curvyCoords[i * 6 + 1] * tileRatio, y: curvyCoords[i * 6 + 0] * tileRatio })
+      const p2 = Geometry.pointAdd(topRightEdge, { x: -shape.right * curvyCoords[i * 6 + 3] * tileRatio, y: curvyCoords[i * 6 + 2] * tileRatio })
+      const p3 = Geometry.pointAdd(topRightEdge, { x: -shape.right * curvyCoords[i * 6 + 5] * tileRatio, y: curvyCoords[i * 6 + 4] * tileRatio })
+      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
+    }
+    const bottomRightEdge = Geometry.pointAdd(topRightEdge, { x: 0, y: tileSize })
+    for (let i = 0; i < curvyCoords.length / 6; i++) {
+      let p1 = Geometry.pointSub(bottomRightEdge, { x: curvyCoords[i * 6 + 0] * tileRatio, y: shape.bottom * curvyCoords[i * 6 + 1] * tileRatio })
+      let p2 = Geometry.pointSub(bottomRightEdge, { x: curvyCoords[i * 6 + 2] * tileRatio, y: shape.bottom * curvyCoords[i * 6 + 3] * tileRatio })
+      let p3 = Geometry.pointSub(bottomRightEdge, { x: curvyCoords[i * 6 + 4] * tileRatio, y: shape.bottom * curvyCoords[i * 6 + 5] * tileRatio })
+      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
+    }
+    const bottomLeftEdge = Geometry.pointSub(bottomRightEdge, { x: tileSize, y: 0 })
+    for (let i = 0; i < curvyCoords.length / 6; i++) {
+      let p1 = Geometry.pointSub(bottomLeftEdge, { x: -shape.left * curvyCoords[i * 6 + 1] * tileRatio, y: curvyCoords[i * 6 + 0] * tileRatio })
+      let p2 = Geometry.pointSub(bottomLeftEdge, { x: -shape.left * curvyCoords[i * 6 + 3] * tileRatio, y: curvyCoords[i * 6 + 2] * tileRatio })
+      let p3 = Geometry.pointSub(bottomLeftEdge, { x: -shape.left * curvyCoords[i * 6 + 5] * tileRatio, y: curvyCoords[i * 6 + 4] * tileRatio })
+      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
+    }
+    paths[key] = path
+    return path
+  }
+
+  for (let tile of tiles) {
+    const srcRect = srcRectByIdx(info, tile.idx)
+    const path = pathForShape(info.shapes[tile.idx])
+
+    const c = Graphics.createCanvas(tileDrawSize, tileDrawSize)
+    const ctx = c.getContext('2d')
+    // -----------------------------------------------------------
+    // -----------------------------------------------------------
+    ctx.lineWidth = 2
+    ctx.stroke(path)
+    // -----------------------------------------------------------
+    // -----------------------------------------------------------
+    ctx.save();
+    ctx.clip(path)
+    ctx.drawImage(
+      img,
+      srcRect.x - tileMarginWidth,
+      srcRect.y - tileMarginWidth,
+      tileDrawSize,
+      tileDrawSize,
+      0,
+      0,
+      tileDrawSize,
+      tileDrawSize,
+    )
+    ctx.stroke(path)
+    ctx.restore();
+
+    bitmaps[tile.idx] = await createImageBitmap(c)
+  }
+
+  return bitmaps
+}
+
+function srcRectByIdx(puzzleInfo, idx) {
+  const c = puzzleInfo.coords[idx]
+  return {
+    x: c.x * puzzleInfo.tileSize,
+    y: c.y * puzzleInfo.tileSize,
+    w: puzzleInfo.tileSize,
+    h: puzzleInfo.tileSize,
+  }
+}
+
+async function loadPuzzleBitmaps(puzzle) {
+  // load bitmap, to determine the original size of the image
+  const bmp = await Graphics.loadImageToBitmap(puzzle.info.imageUrl)
+
+  // creation of tile bitmaps
+  // then create the final puzzle bitmap
+  // NOTE: this can decrease OR increase in size!
+  const bmpResized = await Graphics.resizeBitmap(bmp, puzzle.info.width, puzzle.info.height)
+  return await createPuzzleTileBitmaps(bmpResized, puzzle.tiles, puzzle.info)
+}
+
+export default {
+  loadPuzzleBitmaps,
+}
diff --git a/game/index.js b/game/index.js
index 12a2418..786260b 100644
--- a/game/index.js
+++ b/game/index.js
@@ -1,12 +1,11 @@
 "use strict"
 import {run} from './gameloop.js'
 import Camera from './Camera.js'
-import EventAdapter from './EventAdapter.js'
 import Graphics from './Graphics.js'
 import Debug from './Debug.js'
 import Communication from './Communication.js'
-import Geometry from './../common/Geometry.js'
 import Util from './../common/Util.js'
+import PuzzleGraphics from './PuzzleGraphics.js'
 
 if (typeof GAME_ID === 'undefined') throw '[ GAME_ID not set ]'
 if (typeof WS_ADDRESS === 'undefined') throw '[ WS_ADDRESS not set ]'
@@ -18,121 +17,6 @@ function addCanvasToDom(canvas) {
     return canvas
 }
 
-async function createPuzzleTileBitmaps(img, tiles, info) {
-  var tileSize = info.tileSize
-  var tileMarginWidth = info.tileMarginWidth
-  var tileDrawSize = info.tileDrawSize
-  var tileRatio = tileSize / 100.0
-
-  var curvyCoords = [
-    0, 0, 40, 15, 37, 5,
-    37, 5, 40, 0, 38, -5,
-    38, -5, 20, -20, 50, -20,
-    50, -20, 80, -20, 62, -5,
-    62, -5, 60, 0, 63, 5,
-    63, 5, 65, 15, 100, 0
-  ];
-
-  const bitmaps = new Array(tiles.length)
-
-  const paths = {}
-  function pathForShape(shape) {
-    const key = `${shape.top}${shape.right}${shape.left}${shape.bottom}`
-    if (paths[key]) {
-      return paths[key]
-    }
-
-    const path = new Path2D()
-    const topLeftEdge = { x: tileMarginWidth, y: tileMarginWidth }
-    path.moveTo(topLeftEdge.x, topLeftEdge.y)
-    for (let i = 0; i < curvyCoords.length / 6; i++) {
-      const p1 = Geometry.pointAdd(topLeftEdge, { x: curvyCoords[i * 6 + 0] * tileRatio, y: shape.top * curvyCoords[i * 6 + 1] * tileRatio })
-      const p2 = Geometry.pointAdd(topLeftEdge, { x: curvyCoords[i * 6 + 2] * tileRatio, y: shape.top * curvyCoords[i * 6 + 3] * tileRatio })
-      const p3 = Geometry.pointAdd(topLeftEdge, { x: curvyCoords[i * 6 + 4] * tileRatio, y: shape.top * curvyCoords[i * 6 + 5] * tileRatio })
-      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
-    }
-    const topRightEdge = Geometry.pointAdd(topLeftEdge, { x: tileSize, y: 0 })
-    for (let i = 0; i < curvyCoords.length / 6; i++) {
-      const p1 = Geometry.pointAdd(topRightEdge, { x: -shape.right * curvyCoords[i * 6 + 1] * tileRatio, y: curvyCoords[i * 6 + 0] * tileRatio })
-      const p2 = Geometry.pointAdd(topRightEdge, { x: -shape.right * curvyCoords[i * 6 + 3] * tileRatio, y: curvyCoords[i * 6 + 2] * tileRatio })
-      const p3 = Geometry.pointAdd(topRightEdge, { x: -shape.right * curvyCoords[i * 6 + 5] * tileRatio, y: curvyCoords[i * 6 + 4] * tileRatio })
-      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
-    }
-    const bottomRightEdge = Geometry.pointAdd(topRightEdge, { x: 0, y: tileSize })
-    for (let i = 0; i < curvyCoords.length / 6; i++) {
-      let p1 = Geometry.pointSub(bottomRightEdge, { x: curvyCoords[i * 6 + 0] * tileRatio, y: shape.bottom * curvyCoords[i * 6 + 1] * tileRatio })
-      let p2 = Geometry.pointSub(bottomRightEdge, { x: curvyCoords[i * 6 + 2] * tileRatio, y: shape.bottom * curvyCoords[i * 6 + 3] * tileRatio })
-      let p3 = Geometry.pointSub(bottomRightEdge, { x: curvyCoords[i * 6 + 4] * tileRatio, y: shape.bottom * curvyCoords[i * 6 + 5] * tileRatio })
-      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
-    }
-    const bottomLeftEdge = Geometry.pointSub(bottomRightEdge, { x: tileSize, y: 0 })
-    for (let i = 0; i < curvyCoords.length / 6; i++) {
-      let p1 = Geometry.pointSub(bottomLeftEdge, { x: -shape.left * curvyCoords[i * 6 + 1] * tileRatio, y: curvyCoords[i * 6 + 0] * tileRatio })
-      let p2 = Geometry.pointSub(bottomLeftEdge, { x: -shape.left * curvyCoords[i * 6 + 3] * tileRatio, y: curvyCoords[i * 6 + 2] * tileRatio })
-      let p3 = Geometry.pointSub(bottomLeftEdge, { x: -shape.left * curvyCoords[i * 6 + 5] * tileRatio, y: curvyCoords[i * 6 + 4] * tileRatio })
-      path.bezierCurveTo(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
-    }
-    paths[key] = path
-    return path
-  }
-
-  for (let tile of tiles) {
-    const srcRect = srcRectByIdx(info, tile.idx)
-    const path = pathForShape(info.shapes[tile.idx])
-
-    const c = Graphics.createCanvas(tileDrawSize, tileDrawSize)
-    const ctx = c.getContext('2d')
-    // -----------------------------------------------------------
-    // -----------------------------------------------------------
-    ctx.lineWidth = 2
-    ctx.stroke(path)
-    // -----------------------------------------------------------
-    // -----------------------------------------------------------
-    ctx.save();
-    ctx.clip(path)
-    ctx.drawImage(
-      img,
-      srcRect.x - tileMarginWidth,
-      srcRect.y - tileMarginWidth,
-      tileDrawSize,
-      tileDrawSize,
-      0,
-      0,
-      tileDrawSize,
-      tileDrawSize,
-    )
-    ctx.stroke(path)
-    ctx.restore();
-
-    bitmaps[tile.idx] = await createImageBitmap(c)
-  }
-
-  return bitmaps
-}
-
-function srcRectByIdx(puzzleInfo, idx) {
-  let c = puzzleInfo.coords[idx]
-  let cx = c.x * puzzleInfo.tileSize
-  let cy = c.y * puzzleInfo.tileSize
-  return {
-    x: cx,
-    y: cy,
-    w: puzzleInfo.tileSize,
-    h: puzzleInfo.tileSize,
-  }
-}
-
-async function loadPuzzleBitmaps(puzzle) {
-  // load bitmap, to determine the original size of the image
-  const bmp = await Graphics.loadImageToBitmap(puzzle.info.imageUrl)
-
-  // creation of tile bitmaps
-  // then create the final puzzle bitmap
-  // NOTE: this can decrease OR increase in size!
-  const bmpResized = await Graphics.resizeBitmap(bmp, puzzle.info.width, puzzle.info.height)
-  return await createPuzzleTileBitmaps(bmpResized, puzzle.tiles, puzzle.info)
-}
-
 function initme() {
   // return uniqId()
   let ID = localStorage.getItem("ID")
@@ -152,7 +36,64 @@ const getFirstOwnedTile = (puzzle, userId) => {
   return null
 }
 
-async function main () {
+export default class EventAdapter {
+  constructor(canvas, viewport) {
+    this._mouseEvts = []
+    this._viewport = viewport
+    canvas.addEventListener('mousedown', this._mouseDown.bind(this))
+    canvas.addEventListener('mouseup', this._mouseUp.bind(this))
+    canvas.addEventListener('mousemove', this._mouseMove.bind(this))
+    canvas.addEventListener('wheel', this._wheel.bind(this))
+  }
+
+  consumeAll() {
+    if (this._mouseEvts.length === 0) {
+      return []
+    }
+    const all = this._mouseEvts.slice()
+    this._mouseEvts = []
+    return all
+  }
+
+  _mouseDown(e) {
+    if (e.button === 0) {
+      const pos = this._viewport.viewportToWorld({
+        x: e.offsetX,
+        y: e.offsetY,
+      })
+      this._mouseEvts.push(['down', pos.x, pos.y])
+    }
+  }
+
+  _mouseUp(e) {
+    if (e.button === 0) {
+      const pos = this._viewport.viewportToWorld({
+        x: e.offsetX,
+        y: e.offsetY,
+      })
+      this._mouseEvts.push(['up', pos.x, pos.y])
+    }
+  }
+
+  _mouseMove(e) {
+    const pos = this._viewport.viewportToWorld({
+      x: e.offsetX,
+      y: e.offsetY,
+    })
+    this._mouseEvts.push(['move', pos.x, pos.y])
+  }
+
+  _wheel(e) {
+    const pos = this._viewport.viewportToWorld({
+      x: e.offsetX,
+      y: e.offsetY,
+    })
+    const evt = e.deltaY < 0 ? 'zoomin' : 'zoomout'
+    this._mouseEvts.push([evt, pos.x, pos.y])
+  }
+}
+
+async function main() {
   let gameId = GAME_ID
   let me = initme()
 
@@ -161,7 +102,7 @@ async function main () {
 
   const game = await Communication.connect(gameId, me)
 
-  const bitmaps = await loadPuzzleBitmaps(game.puzzle)
+  const bitmaps = await PuzzleGraphics.loadPuzzleBitmaps(game.puzzle)
   const puzzle = game.puzzle
   const players = game.players
 
@@ -176,7 +117,6 @@ async function main () {
   // Create a dom and attach adapters to it so we can work with it
   const canvas = addCanvasToDom(Graphics.createCanvas())
   const ctx = canvas.getContext('2d')
-  const evts = new EventAdapter(canvas)
 
   // initialize some view data
   // this global data will change according to input events
@@ -187,21 +127,27 @@ async function main () {
     -(puzzle.info.table.height - viewport.height) /2
   )
 
-  Communication.onChanges((changes) => {
-    for (let [type, typeData] of changes) {
-      switch (type) {
+  const evts = new EventAdapter(canvas, viewport)
+
+  Communication.onServerChange((msg) => {
+    const msgType = msg[0]
+    const evClientId = msg[1]
+    const evClientSeq = msg[2]
+    const evChanges = msg[3]
+    for(let [changeType, changeData] of evChanges) {
+      switch (changeType) {
         case 'player': {
-          if (typeData.id !== me) {
-            players[typeData.id] = typeData
+          if (changeData.id !== me) {
+            players[changeData.id] = changeData
             rerender = true
           }
         } break;
         case 'tile': {
-          puzzle.tiles[typeData.idx] = typeData
+          puzzle.tiles[changeData.idx] = changeData
           rerender = true
         } break;
         case 'data': {
-          puzzle.data = typeData
+          puzzle.data = changeData
           rerender = true
         } break;
       }
@@ -217,40 +163,41 @@ async function main () {
     return sorted.sort((t1, t2) => t1.z - t2.z)
   }
 
-
   let _last_mouse_down = null
   const onUpdate = () => {
-    for (let mouse of evts.consumeAll()) {
-      const tp = viewport.viewportToWorld(mouse)
+    for (let evt of evts.consumeAll()) {
+      const type = evt[0]
+      const pos = {x: evt[1], y: evt[2]}
 
-      if (mouse.type === 'move') {
-        Communication.addMouse(['move', tp.x, tp.y])
+      if (type === 'move') {
         rerender = true
-        changePlayer({ x: tp.x, y: tp.y })
+        changePlayer(pos)
 
         if (_last_mouse_down && !getFirstOwnedTile(puzzle, me)) {
             // move the cam
+            const mouse = viewport.worldToViewport(pos)
             const diffX = Math.round(mouse.x - _last_mouse_down.x)
             const diffY = Math.round(mouse.y - _last_mouse_down.y)
             viewport.move(diffX, diffY)
 
             _last_mouse_down = mouse
         }
-      } else if (mouse.type === 'down') {
-        Communication.addMouse(['down', tp.x, tp.y])
-        _last_mouse_down = mouse
-      } else if (mouse.type === 'up') {
-        Communication.addMouse(['up', tp.x, tp.y])
+      } else if (type === 'down') {
+        _last_mouse_down = viewport.worldToViewport(pos)
+      } else if (type === 'up') {
         _last_mouse_down = null
-      } else if (mouse.type === 'wheel') {
-        if (
-          mouse.deltaY < 0 && viewport.zoomIn()
-          || mouse.deltaY > 0 && viewport.zoomOut()
-        ) {
+      } else if (type === 'zoomin') {
+        if (viewport.zoomIn()) {
           rerender = true
-          changePlayer({ x: tp.x, y: tp.y })
+          changePlayer(pos)
+        }
+      } else if (type === 'zoomout') {
+        if (viewport.zoomOut()) {
+          rerender = true
+          changePlayer(pos)
         }
       }
+      Communication.sendClientEvent(evt)
     }
   }
 
diff --git a/server/index.js b/server/index.js
index b241553..0c3224c 100644
--- a/server/index.js
+++ b/server/index.js
@@ -2,14 +2,10 @@ import WebSocketServer from './WebSocketServer.js'
 
 import express from 'express'
 import config from './config.js'
+import Protocol from './../common/Protocol.js'
 import Util from './../common/Util.js'
 import Game from './Game.js'
 
-const EV_SERVER_STATE_CHANGED = 1
-const EV_SERVER_INIT = 4
-const EV_CLIENT_MOUSE = 2
-const EV_CLIENT_INIT = 3
-
 // desired number of tiles
 // actual calculated number can be higher
 const TARGET_TILES = 1000
@@ -65,35 +61,41 @@ app.use('/', (req, res, next) => {
 const wss = new WebSocketServer(config.ws);
 
 const notify = (data, sockets) => {
-  // TODO: throttle
+  // TODO: throttle?
   for (let socket of sockets) {
     wss.notifyOne(data, socket)
   }
-  // console.log('notify', data)
 }
 
 wss.on('message', async ({socket, data}) => {
   try {
     const proto = socket.protocol.split('|')
-    const playerId = proto[0]
+    const clientId = proto[0]
     const gameId = proto[1]
-    const [type, typeData] = JSON.parse(data)
-    switch (type) {
-      case EV_CLIENT_INIT: {
+    const msg = JSON.parse(data)
+    const msgType = msg[0]
+    switch (msgType) {
+      case Protocol.EV_CLIENT_INIT: {
         if (!Game.exists(gameId)) {
           await Game.createGame(gameId, TARGET_TILES, Util.choice(IMAGES))
         }
-        Game.addPlayer(gameId, playerId)
+        Game.addPlayer(gameId, clientId)
         Game.addSocket(gameId, socket)
 
-        wss.notifyOne([EV_SERVER_INIT, Game.get(gameId)], socket)
+        notify(
+          [Protocol.EV_SERVER_INIT, Game.get(gameId)],
+          [socket]
+        )
       } break;
 
-      case EV_CLIENT_MOUSE: {
-        const changes = Game.handleInput(gameId, playerId, typeData)
-        if (changes.length > 0) {
-          notify([EV_SERVER_STATE_CHANGED, changes], Game.getSockets(gameId))
-        }
+      case Protocol.EV_CLIENT_EVENT: {
+        const clientSeq = msg[1]
+        const clientEvtData = msg[2]
+        const changes = Game.handleInput(gameId, clientId, clientEvtData)
+        notify(
+          [Protocol.EV_SERVER_EVENT, clientId, clientSeq, changes],
+          Game.getSockets(gameId)
+        )
       } break;
     }
   } catch (e) {