diff --git a/docs/examples/audio.html b/docs/examples/audio.html
index 1c3b9d478..5c957d860 100644
--- a/docs/examples/audio.html
+++ b/docs/examples/audio.html
@@ -46,6 +46,10 @@ import (
 const (
         screenWidth  = 320
         screenHeight = 240
+
+        // This sample rate doesn't match with wav/ogg's sample rate,
+        // but decoders adjust them.
+        sampleRate = 48000
 )
 
 var (
@@ -54,39 +58,59 @@ var (
 )
 
 func init() {
-        var err error
-        playerBarImage, err = ebiten.NewImage(300, 4, ebiten.FilterNearest)
-        if err != nil {
-                log.Fatal(err)
-        }
-        if err := playerBarImage.Fill(&color.RGBA{0x80, 0x80, 0x80, 0xff}); err != nil {
-                log.Fatal(err)
-        }
+        playerBarImage, _ = ebiten.NewImage(300, 4, ebiten.FilterNearest)
+        playerBarImage.Fill(&color.RGBA{0x80, 0x80, 0x80, 0xff})
 
-        playerCurrentImage, err = ebiten.NewImage(4, 10, ebiten.FilterNearest)
-        if err != nil {
-                log.Fatal(err)
+        playerCurrentImage, _ = ebiten.NewImage(4, 10, ebiten.FilterNearest)
+        playerCurrentImage.Fill(&color.RGBA{0xff, 0xff, 0xff, 0xff})
+}
+
+type Input struct {
+        mouseButtonStates map[ebiten.MouseButton]int
+        keyStates         map[ebiten.Key]int
+}
+
+func (i *Input) update() {
+        for _, key := range []ebiten.Key{ebiten.KeyP, ebiten.KeyS, ebiten.KeyX, ebiten.KeyZ} {
+                if !ebiten.IsKeyPressed(key) {
+                        i.keyStates[key] = 0
+                } else {
+                        i.keyStates[key]++
+                }
         }
-        if err := playerCurrentImage.Fill(&color.RGBA{0xff, 0xff, 0xff, 0xff}); err != nil {
-                log.Fatal(err)
+        if !ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft) {
+                i.mouseButtonStates[ebiten.MouseButtonLeft] = 0
+        } else {
+                i.mouseButtonStates[ebiten.MouseButtonLeft]++
         }
 }
 
+func (i *Input) isKeyTriggered(key ebiten.Key) bool {
+        return i.keyStates[key] == 1
+}
+
+func (i *Input) isKeyPressed(key ebiten.Key) bool {
+        return i.keyStates[key] > 0
+}
+
+func (i *Input) isMouseButtonTriggered(mouseButton ebiten.MouseButton) bool {
+        return i.mouseButtonStates[mouseButton] == 1
+}
+
 type Player struct {
-        audioPlayer *audio.Player
-        total       time.Duration
-        seekedCh    chan error
+        input        *Input
+        audioContext *audio.Context
+        audioPlayer  *audio.Player
+        total        time.Duration
+        seekedCh     chan error
+        seBytes      []uint8
+        seCh         chan []uint8
+        volume128    int
+        previousPos  time.Duration
 }
 
 var (
-        audioContext     *audio.Context
-        musicPlayer      *Player
-        seBytes          []byte
-        musicCh          = make(chan *Player)
-        seCh             = make(chan []byte)
-        mouseButtonState = map[ebiten.MouseButton]int{}
-        keyState         = map[ebiten.Key]int{}
-        volume128        = 128
+        musicPlayer *Player
 )
 
 func playerBarRect() (x, y, w, h int) {
@@ -96,77 +120,122 @@ func playerBarRect() (x, y, w, h int) {
         return
 }
 
-func (p *Player) updateSE() error {
-        if seBytes == nil {
-                return nil
-        }
-        if !ebiten.IsKeyPressed(ebiten.KeyP) {
-                keyState[ebiten.KeyP] = 0
-                return nil
-        }
-        keyState[ebiten.KeyP]++
-        if keyState[ebiten.KeyP] != 1 {
-                return nil
-        }
-        sePlayer, err := audio.NewPlayerFromBytes(audioContext, seBytes)
+func NewPlayer(audioContext *audio.Context) (*Player, error) {
+        const bytesPerSample = 4 // TODO: This should be defined in audio package
+        wavF, err := ebitenutil.OpenFile("_resources/audio/jab.wav")
         if err != nil {
+                return nil, err
+        }
+        oggF, err := ebitenutil.OpenFile("_resources/audio/ragtime.ogg")
+        if err != nil {
+                return nil, err
+        }
+        s, err := vorbis.Decode(audioContext, oggF)
+        if err != nil {
+                return nil, err
+        }
+        p, err := audio.NewPlayer(audioContext, s)
+        if err != nil {
+                return nil, err
+        }
+        player := &Player{
+                input: &Input{
+                        mouseButtonStates: map[ebiten.MouseButton]int{},
+                        keyStates:         map[ebiten.Key]int{},
+                },
+                audioContext: audioContext,
+                audioPlayer:  p,
+                total:        time.Second * time.Duration(s.Size()) / bytesPerSample / sampleRate,
+                volume128:    128,
+                seCh:         make(chan []uint8),
+        }
+        player.audioPlayer.Play()
+        go func() {
+                s, err := wav.Decode(audioContext, wavF)
+                if err != nil {
+                        log.Fatal(err)
+                        return
+                }
+                b, err := ioutil.ReadAll(s)
+                if err != nil {
+                        log.Fatal(err)
+                        return
+                }
+                player.seCh <- b
+        }()
+        return player, nil
+}
+
+func (p *Player) update() error {
+        p.input.update()
+        select {
+        case p.seBytes = <-p.seCh:
+                close(p.seCh)
+                p.seCh = nil
+        case err := <-p.seekedCh:
+                if err != nil {
+                        return err
+                }
+                close(p.seekedCh)
+                p.seekedCh = nil
+        default:
+        }
+        p.updateBar()
+        p.updatePlayPause()
+        p.updateSE()
+        p.updateVolume()
+        if err := p.audioContext.Update(); err != nil {
                 return err
         }
-        return sePlayer.Play()
+        return nil
+}
+
+func (p *Player) updateSE() {
+        if p.seBytes == nil {
+                return
+        }
+        if !p.input.isKeyTriggered(ebiten.KeyP) {
+                return
+        }
+        sePlayer, _ := audio.NewPlayerFromBytes(p.audioContext, p.seBytes)
+        sePlayer.Play()
 }
 
 func (p *Player) updateVolume() {
-        if p.audioPlayer == nil {
-                return
+        if p.input.isKeyPressed(ebiten.KeyZ) {
+                p.volume128--
         }
-        if ebiten.IsKeyPressed(ebiten.KeyZ) {
-                volume128--
+        if p.input.isKeyPressed(ebiten.KeyX) {
+                p.volume128++
         }
-        if ebiten.IsKeyPressed(ebiten.KeyX) {
-                volume128++
+        if p.volume128 < 0 {
+                p.volume128 = 0
         }
-        if volume128 < 0 {
-                volume128 = 0
+        if 128 < p.volume128 {
+                p.volume128 = 128
         }
-        if 128 < volume128 {
-                volume128 = 128
-        }
-        p.audioPlayer.SetVolume(float64(volume128) / 128)
+        p.audioPlayer.SetVolume(float64(p.volume128) / 128)
 }
 
-func (p *Player) updatePlayPause() error {
-        if p.audioPlayer == nil {
-                return nil
-        }
-        if !ebiten.IsKeyPressed(ebiten.KeyS) {
-                keyState[ebiten.KeyS] = 0
-                return nil
-        }
-        keyState[ebiten.KeyS]++
-        if keyState[ebiten.KeyS] != 1 {
-                return nil
+func (p *Player) updatePlayPause() {
+        if !p.input.isKeyTriggered(ebiten.KeyS) {
+                return
         }
         if p.audioPlayer.IsPlaying() {
-                return p.audioPlayer.Pause()
+                p.audioPlayer.Pause()
+                return
         }
-        return p.audioPlayer.Play()
+        p.audioPlayer.Play()
 }
 
 func (p *Player) updateBar() {
-        if p.audioPlayer == nil {
-                return
-        }
         if p.seekedCh != nil {
                 return
         }
-        if !ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft) {
-                mouseButtonState[ebiten.MouseButtonLeft] = 0
-                return
-        }
-        mouseButtonState[ebiten.MouseButtonLeft]++
-        if mouseButtonState[ebiten.MouseButtonLeft] != 1 {
+        if !p.input.isMouseButtonTriggered(ebiten.MouseButtonLeft) {
                 return
         }
+        // Start seeking.
         x, y := ebiten.CursorPosition()
         bx, by, bw, bh := playerBarRect()
         const padding = 4
@@ -179,7 +248,6 @@ func (p *Player) updateBar() {
         pos := time.Duration(x-bx) * p.total / time.Duration(bw)
         p.seekedCh = make(chan error, 1)
         go func() {
-                // This can't be done parallely! !?!?
                 p.seekedCh <- p.audioPlayer.Seek(pos)
         }()
 }
@@ -188,133 +256,60 @@ func (p *Player) close() error {
         return p.audioPlayer.Close()
 }
 
-func update(screen *ebiten.Image) error {
-        if musicPlayer == nil {
-                select {
-                case musicPlayer = <-musicCh:
-                default:
-                }
-        }
-        if seBytes == nil {
-                select {
-                case seBytes = <-seCh:
-                default:
-                }
-        }
-        if musicPlayer != nil {
-                musicPlayer.updateBar()
-                if err := musicPlayer.updatePlayPause(); err != nil {
-                        return err
-                }
-                if err := musicPlayer.updateSE(); err != nil {
-                        return err
-                }
-                musicPlayer.updateVolume()
-        }
-        if ebiten.IsRunningSlowly() {
-                return nil
-        }
+func (p *Player) draw(screen *ebiten.Image) {
         op := &ebiten.DrawImageOptions{}
         x, y, w, h := playerBarRect()
         op.GeoM.Translate(float64(x), float64(y))
         screen.DrawImage(playerBarImage, op)
         currentTimeStr := "00:00"
-        if musicPlayer != nil {
-                c := musicPlayer.audioPlayer.Current()
+        c := p.audioPlayer.Current()
+        prev := p.previousPos
+        p.previousPos = c
 
-                // Current Time
-                m := (c / time.Minute) % 100
-                s := (c / time.Second) % 60
-                currentTimeStr = fmt.Sprintf("%02d:%02d", m, s)
+        // Current Time
+        m := (c / time.Minute) % 100
+        s := (c / time.Second) % 60
+        currentTimeStr = fmt.Sprintf("%02d:%02d", m, s)
 
-                // Bar
-                cw, ch := playerCurrentImage.Size()
-                cx := int(time.Duration(w)*c/musicPlayer.total) + x - cw/2
-                cy := y - (ch-h)/2
-                op := &ebiten.DrawImageOptions{}
-                op.GeoM.Translate(float64(cx), float64(cy))
-                screen.DrawImage(playerCurrentImage, op)
-        }
+        // Bar
+        cw, ch := playerCurrentImage.Size()
+        cx := int(time.Duration(w)*c/p.total) + x - cw/2
+        cy := y - (ch-h)/2
+        op = &ebiten.DrawImageOptions{}
+        op.GeoM.Translate(float64(cx), float64(cy))
+        screen.DrawImage(playerCurrentImage, op)
 
         msg := fmt.Sprintf(`FPS: %0.2f
 Press S to toggle Play/Pause
 Press P to play SE
 Press Z or X to change volume of the music
 %s`, ebiten.CurrentFPS(), currentTimeStr)
-        if musicPlayer == nil {
-                msg += "\nNow Loading..."
-        } else if musicPlayer.seekedCh != nil {
-                select {
-                case err := <-musicPlayer.seekedCh:
-                        if err != nil {
-                                return err
-                        }
-                        close(musicPlayer.seekedCh)
-                        musicPlayer.seekedCh = nil
-                default:
-                        msg += "\nSeeking..."
-                }
+        if p.audioPlayer.IsPlaying() && prev == c {
+                msg += "\nLoading..."
         }
         ebitenutil.DebugPrint(screen, msg)
-        if err := audioContext.Update(); err != nil {
+}
+
+func update(screen *ebiten.Image) error {
+        if err := musicPlayer.update(); err != nil {
                 return err
         }
+        if ebiten.IsRunningSlowly() {
+                return nil
+        }
+        musicPlayer.draw(screen)
         return nil
 }
 
 func main() {
-        wavF, err := ebitenutil.OpenFile("_resources/audio/jab.wav")
+        audioContext, err := audio.NewContext(sampleRate)
         if err != nil {
                 log.Fatal(err)
         }
-        oggF, err := ebitenutil.OpenFile("_resources/audio/game.ogg")
+        musicPlayer, err = NewPlayer(audioContext)
         if err != nil {
                 log.Fatal(err)
         }
-        // This sample rate doesn't match with wav/ogg's sample rate,
-        // but decoders adjust them.
-        const sampleRate = 48000
-        const bytesPerSample = 4 // TODO: This should be defined in audio package
-        audioContext, err = audio.NewContext(sampleRate)
-        if err != nil {
-                log.Fatal(err)
-        }
-        go func() {
-                s, err := wav.Decode(audioContext, wavF)
-                if err != nil {
-                        log.Fatal(err)
-                        return
-                }
-                b, err := ioutil.ReadAll(s)
-                if err != nil {
-                        log.Fatal(err)
-                        return
-                }
-                seCh <- b
-                close(seCh)
-        }()
-        go func() {
-                s, err := vorbis.Decode(audioContext, oggF)
-                if err != nil {
-                        log.Fatal(err)
-                        return
-                }
-                p, err := audio.NewPlayer(audioContext, s)
-                if err != nil {
-                        log.Fatal(err)
-                        return
-                }
-                musicCh <- &Player{
-                        audioPlayer: p,
-                        total:       time.Second * time.Duration(s.Size()) / bytesPerSample / sampleRate,
-                }
-                close(musicCh)
-                // TODO: Is this goroutine-safe?
-                if err := p.Play(); err != nil {
-                        log.Fatal(err)
-                        return
-                }
-        }()
         if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Audio (Ebiten Demo)"); err != nil {
                 log.Fatal(err)
         }
diff --git a/docs/examples/infinitescroll.html b/docs/examples/infinitescroll.html
index b1ac9db45..a4b0f80bc 100644
--- a/docs/examples/infinitescroll.html
+++ b/docs/examples/infinitescroll.html
@@ -130,7 +130,7 @@ func main() {
         }
         groundImage, _ = ebiten.NewImage(screenWidth, screenHeight, ebiten.FilterNearest)
 
-        if err := ebiten.Run(update, screenWidth, screenHeight, 2, "infinite scroll"); err != nil {
+        if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Infinite Scroll (Ebiten Demo)"); err != nil {
                 log.Fatal(err)
         }
 }
diff --git a/docs/examples/life.html b/docs/examples/life.html
index 8d3ce25df..ebef0e103 100644
--- a/docs/examples/life.html
+++ b/docs/examples/life.html
@@ -30,7 +30,6 @@
 package main
 
 import (
-        "image"
         "log"
         "math/rand"
         "time"
@@ -38,20 +37,18 @@ import (
         "github.com/hajimehoshi/ebiten"
 )
 
-var (
-        randSource = rand.NewSource(time.Now().UnixNano())
-        rnd        = rand.New(randSource)
-)
-
 // World represents the game state
 type World struct {
         area [][]bool
+        rnd  *rand.Rand
 }
 
 // NewWorld creates a new world
 func NewWorld(width, height int) *World {
-        world := World{}
-        world.area = makeArea(width, height)
+        world := World{
+                area: makeArea(width, height),
+                rnd:  rand.New(rand.NewSource(time.Now().UnixNano())),
+        }
         return &world
 }
 
@@ -59,10 +56,9 @@ func NewWorld(width, height int) *World {
 func (w *World) RandomSeed(limit int) {
         height := len(w.area)
         width := len(w.area[0])
-
         for i := 0; i < limit; i++ {
-                x := rnd.Intn(width)
-                y := rnd.Intn(height)
+                x := w.rnd.Intn(width)
+                y := w.rnd.Intn(height)
                 w.area[y][x] = true
         }
 }
@@ -71,9 +67,7 @@ func (w *World) RandomSeed(limit int) {
 func (w *World) Progress() {
         height := len(w.area)
         width := len(w.area[0])
-
         next := makeArea(width, height)
-
         for y := 0; y < height; y++ {
                 for x := 0; x < width; x++ {
 
@@ -105,23 +99,22 @@ func (w *World) Progress() {
 }
 
 // DrawImage paints current game state
-func (w *World) DrawImage(img *image.RGBA) {
+func (w *World) DrawImage(pix []uint8) {
         height := len(w.area)
         width := len(w.area[0])
-
         for y := 0; y < height; y++ {
                 for x := 0; x < width; x++ {
                         pos := 4*y*width + 4*x
                         if w.area[y][x] {
-                                img.Pix[pos] = 0xff
-                                img.Pix[pos+1] = 0xff
-                                img.Pix[pos+2] = 0xff
-                                img.Pix[pos+3] = 0xff
+                                pix[pos] = 0xff
+                                pix[pos+1] = 0xff
+                                pix[pos+2] = 0xff
+                                pix[pos+3] = 0xff
                         } else {
-                                img.Pix[pos] = 0
-                                img.Pix[pos+1] = 0
-                                img.Pix[pos+2] = 0
-                                img.Pix[pos+3] = 0
+                                pix[pos] = 0
+                                pix[pos+1] = 0
+                                pix[pos+2] = 0
+                                pix[pos+3] = 0
                         }
                 }
         }
@@ -131,27 +124,22 @@ func (w *World) DrawImage(img *image.RGBA) {
 func neighbourCount(a [][]bool, x, y int) int {
         height := len(a)
         width := len(a[0])
-
         lowX := 0
         if x > 0 {
                 lowX = x - 1
         }
-
         lowY := 0
         if y > 0 {
                 lowY = y - 1
         }
-
         highX := width - 1
         if x < width-1 {
                 highX = x + 1
         }
-
         highY := height - 1
         if y < height-1 {
                 highY = y + 1
         }
-
         near := 0
         for pY := lowY; pY <= highY; pY++ {
                 for pX := lowX; pX <= highX; pX++ {
@@ -178,8 +166,8 @@ const (
 )
 
 var (
-        world      *World
-        noiseImage *image.RGBA
+        world  = NewWorld(screenWidth, screenHeight)
+        pixels = make([]uint8, screenWidth*screenHeight*4)
 )
 
 func update(screen *ebiten.Image) error {
@@ -187,20 +175,14 @@ func update(screen *ebiten.Image) error {
         if ebiten.IsRunningSlowly() {
                 return nil
         }
-        world.DrawImage(noiseImage)
-        screen.ReplacePixels(noiseImage.Pix)
+        world.DrawImage(pixels)
+        screen.ReplacePixels(pixels)
         return nil
 }
 
 func main() {
-        population := int((screenWidth * screenHeight) / 10)
-        scale := 2.0
-
-        world = NewWorld(screenWidth, screenHeight)
-        world.RandomSeed(population)
-
-        noiseImage = image.NewRGBA(image.Rect(0, 0, screenWidth, screenHeight))
-        if err := ebiten.Run(update, screenWidth, screenHeight, scale, "Game of Life (Ebiten Demo)"); err != nil {
+        world.RandomSeed(int((screenWidth * screenHeight) / 10))
+        if err := ebiten.Run(update, screenWidth, screenHeight, 2.0, "Game of Life (Ebiten Demo)"); err != nil {
                 log.Fatal(err)
         }
 }
diff --git a/docs/examples/paint.html b/docs/examples/paint.html
index 80cdd62d7..336a8ad68 100644
--- a/docs/examples/paint.html
+++ b/docs/examples/paint.html
@@ -55,7 +55,7 @@ func paint(screen *ebiten.Image, x, y int) {
         op := &ebiten.DrawImageOptions{}
         op.GeoM.Translate(float64(x), float64(y))
         op.ColorM.Scale(1.0, 0.50, 0.125, 1.0)
-        theta := 2.0 * math.Pi * float64(count%60) / ebiten.FPS
+        theta := 2.0 * math.Pi * float64(count%ebiten.FPS) / ebiten.FPS
         op.ColorM.RotateHue(theta)
         canvasImage.DrawImage(brushImage, op)
 }
diff --git a/docs/examples/piano.html b/docs/examples/piano.html
index c5be21dff..9ebcb8a80 100644
--- a/docs/examples/piano.html
+++ b/docs/examples/piano.html
@@ -94,20 +94,15 @@ func toBytes(l, r []int16) []byte {
         return b
 }
 
-func addNote(freq float64, vol float64) error {
+func addNote(freq float64, vol float64) {
         // TODO: Call Close method of *audio.Player.
         // However, this works without Close because Close is automatically called when GC
         // collects a *audio.Player object.
         f := int(freq)
         if n, ok := noteCache[f]; ok {
-                p, err := audio.NewPlayerFromBytes(audioContext, n)
-                if err != nil {
-                        return err
-                }
-                if err := p.Play(); err != nil {
-                        return err
-                }
-                return nil
+                p, _ := audio.NewPlayerFromBytes(audioContext, n)
+                p.Play()
+                return
         }
         length := len(pcm) * baseFreq / f
         l := make([]int16, length)
@@ -123,14 +118,9 @@ func addNote(freq float64, vol float64) error {
         }
         n := toBytes(l, r)
         noteCache[f] = n
-        p, err := audio.NewPlayerFromBytes(audioContext, n)
-        if err != nil {
-                return err
-        }
-        if err := p.Play(); err != nil {
-                return err
-        }
-        return nil
+        p, _ := audio.NewPlayerFromBytes(audioContext, n)
+        p.Play()
+        return
 }
 
 var keys = []ebiten.Key{
@@ -216,9 +206,10 @@ func update(screen *ebiten.Image) error {
                 if keyStates[key] != 1 {
                         continue
                 }
-                if err := addNote(220*math.Exp2(float64(i-1)/12.0), 1.0); err != nil {
-                        return err
-                }
+                addNote(220*math.Exp2(float64(i-1)/12.0), 1.0)
+        }
+        if err := audioContext.Update(); err != nil {
+                return err
         }
         if ebiten.IsRunningSlowly() {
                 return nil
@@ -227,10 +218,6 @@ func update(screen *ebiten.Image) error {
         screen.DrawImage(imagePiano, nil)
 
         ebitenutil.DebugPrint(screen, fmt.Sprintf("FPS: %0.2f", ebiten.CurrentFPS()))
-
-        if err := audioContext.Update(); err != nil {
-                return err
-        }
         return nil
 }
 
diff --git a/docs/index.html b/docs/index.html
index ff6e433e7..6b6c79a1c 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -31,7 +31,7 @@
 <main><div class="container">
   <h1>Ebiten</h1>
   <p class="lead">A simple 2D game library in Go</p>
-  <p>Stable version: v1.4.0-rc1 / Development version: v1.5.0-alpha</p>
+  <p>Stable version: v1.5.0 / Development version: v1.6.0-alpha</p>
 
   <h2 id="platforms">Platforms</h2>
   <dl class="dl-horizontal">