diff --git a/Common/Drawable.go b/Common/Drawable.go
new file mode 100644
index 00000000..bd301b81
--- /dev/null
+++ b/Common/Drawable.go
@@ -0,0 +1,13 @@
+package Common
+
+import "github.com/hajimehoshi/ebiten"
+
+// Drawable represents an instance that can be drawn
+type Drawable interface {
+	Draw(target *ebiten.Image)
+	GetSize() (uint32, uint32)
+	MoveTo(x, y int)
+	GetLocation() (int, int)
+	GetVisible() bool
+	SetVisible(bool)
+}
diff --git a/Engine.go b/Engine.go
index 3bf1f539..227676bd 100644
--- a/Engine.go
+++ b/Engine.go
@@ -9,6 +9,7 @@ import (
 	"sync"
 
 	"github.com/essial/OpenDiablo2/Common"
+	"github.com/essial/OpenDiablo2/Palettes"
 	"github.com/essial/OpenDiablo2/ResourcePaths"
 
 	"github.com/hajimehoshi/ebiten"
@@ -27,31 +28,34 @@ type EngineConfig struct {
 	MpqLoadOrder    []string
 }
 
-// Engine is the core OpenDiablo2 engine
+// CursorButton represents a mouse button
 type CursorButton uint8
 
 const (
-	CursorButtonLeft  CursorButton = 1
+	// CursorButtonLeft represents the left mouse button
+	CursorButtonLeft CursorButton = 1
+	// CursorButtonRight represents the right mouse button
 	CursorButtonRight CursorButton = 2
 )
 
+// Engine is the core OpenDiablo2 engine
 type Engine struct {
-	Settings        EngineConfig          // Engine configuration settings from json file
-	Files           map[string]string     // Map that defines which files are in which MPQs
-	Palettes        map[string]Palette    // Color palettes
-	SoundEntries    map[string]SoundEntry // Sound configurations
-	CursorSprite    Sprite                // The sprite shown for cursors
-	LoadingSprite   Sprite                // The sprite shown when loading stuff
-	CursorX         int                   // X position of the cursor
-	CursorY         int                   // Y position of the cursor
-	CursorButtons   CursorButton          // The buttons that are currently being pressed
-	LoadingProgress float64               // LoadingProcess is a range between 0.0 and 1.0. If set, loading screen displays.
-	CurrentScene    Common.SceneInterface // The current scene being rendered
-	nextScene       Common.SceneInterface // The next scene to be loaded at the end of the game loop
-	fontCache       map[string]*MPQFont   // The font cash
-	audioContext    *audio.Context        // The Audio context
-	bgmAudio        *audio.Player         // The audio player
-	fullscreenKey   bool                  // When true, the fullscreen toggle is still being pressed
+	Settings        EngineConfig                 // Engine configuration settings from json file
+	Files           map[string]string            // Map that defines which files are in which MPQs
+	Palettes        map[Palettes.Palette]Palette // Color palettes
+	SoundEntries    map[string]SoundEntry        // Sound configurations
+	CursorSprite    *Sprite                      // The sprite shown for cursors
+	LoadingSprite   *Sprite                      // The sprite shown when loading stuff
+	CursorX         int                          // X position of the cursor
+	CursorY         int                          // Y position of the cursor
+	CursorButtons   CursorButton                 // The buttons that are currently being pressed
+	LoadingProgress float64                      // LoadingProcess is a range between 0.0 and 1.0. If set, loading screen displays.
+	CurrentScene    Common.SceneInterface        // The current scene being rendered
+	nextScene       Common.SceneInterface        // The next scene to be loaded at the end of the game loop
+	fontCache       map[string]*MPQFont          // The font cash
+	audioContext    *audio.Context               // The Audio context
+	bgmAudio        *audio.Player                // The audio player
+	fullscreenKey   bool                         // When true, the fullscreen toggle is still being pressed
 }
 
 // CreateEngine creates and instance of the OpenDiablo2 engine
@@ -71,8 +75,8 @@ func CreateEngine() *Engine {
 		log.Fatal(err)
 	}
 	result.audioContext = audioContext
-	result.CursorSprite = result.LoadSprite(ResourcePaths.CursorDefault, result.Palettes["units"])
-	result.LoadingSprite = result.LoadSprite(ResourcePaths.LoadingScreen, result.Palettes["loading"])
+	result.CursorSprite = result.LoadSprite(ResourcePaths.CursorDefault, Palettes.Units)
+	result.LoadingSprite = result.LoadSprite(ResourcePaths.LoadingScreen, Palettes.Loading)
 	loadingSpriteSizeX, loadingSpriteSizeY := result.LoadingSprite.GetSize()
 	result.LoadingSprite.MoveTo(int(400-(loadingSpriteSizeX/2)), int(300+(loadingSpriteSizeY/2)))
 	result.SetNextScene(CreateMainMenu(result))
@@ -142,14 +146,14 @@ func (v *Engine) IsLoading() bool {
 }
 
 func (v *Engine) loadPalettes() {
-	v.Palettes = make(map[string]Palette)
+	v.Palettes = make(map[Palettes.Palette]Palette)
 	log.Println("loading palettes")
 	for file := range v.Files {
 		if strings.Index(file, "/data/global/palette/") != 0 || strings.Index(file, ".dat") != len(file)-4 {
 			continue
 		}
 		nameParts := strings.Split(file, `/`)
-		paletteName := nameParts[len(nameParts)-2]
+		paletteName := Palettes.Palette(nameParts[len(nameParts)-2])
 		palette := CreatePalette(paletteName, v.GetFile(file))
 		v.Palettes[paletteName] = palette
 	}
@@ -169,9 +173,9 @@ func (v *Engine) loadSoundEntries() {
 }
 
 // LoadSprite loads a sprite from the game's data files
-func (v *Engine) LoadSprite(fileName string, palette Palette) Sprite {
+func (v *Engine) LoadSprite(fileName string, palette Palettes.Palette) *Sprite {
 	data := v.GetFile(fileName)
-	sprite := CreateSprite(data, palette)
+	sprite := CreateSprite(data, v.Palettes[palette])
 	return sprite
 }
 
@@ -241,13 +245,13 @@ func (v *Engine) SetNextScene(nextScene Common.SceneInterface) {
 }
 
 // GetFont creates or loads an existing font
-func (v *Engine) GetFont(font, palette string) *MPQFont {
-	cacheItem, exists := v.fontCache[font+"_"+palette]
+func (v *Engine) GetFont(font string, palette Palettes.Palette) *MPQFont {
+	cacheItem, exists := v.fontCache[font+"_"+string(palette)]
 	if exists {
 		return cacheItem
 	}
-	newFont := CreateMPQFont(v, font, v.Palettes[palette])
-	v.fontCache[font+"_"+palette] = newFont
+	newFont := CreateMPQFont(v, font, palette)
+	v.fontCache[font+"_"+string(palette)] = newFont
 	return newFont
 }
 
diff --git a/MPQFont.go b/MPQFont.go
index 731078d5..1bb7288e 100644
--- a/MPQFont.go
+++ b/MPQFont.go
@@ -1,18 +1,22 @@
 package OpenDiablo2
 
+import "github.com/essial/OpenDiablo2/Palettes"
+
+// MPQFontSize represents the size of a character in a font
 type MPQFontSize struct {
 	Width  uint8
 	Height uint8
 }
 
+// MPQFont represents a font
 type MPQFont struct {
 	Engine     *Engine
-	FontSprite Sprite
+	FontSprite *Sprite
 	Metrics    map[uint8]MPQFontSize
 }
 
 // CreateMPQFont creates an instance of a MPQ Font
-func CreateMPQFont(engine *Engine, font string, palette Palette) *MPQFont {
+func CreateMPQFont(engine *Engine, font string, palette Palettes.Palette) *MPQFont {
 	result := &MPQFont{
 		Engine:  engine,
 		Metrics: make(map[uint8]MPQFontSize),
diff --git a/Palette.go b/Palette.go
index a77b544c..67317096 100644
--- a/Palette.go
+++ b/Palette.go
@@ -1,17 +1,20 @@
 package OpenDiablo2
 
+import "github.com/essial/OpenDiablo2/Palettes"
+
+// PaletteRGB represents a color in a palette
 type PaletteRGB struct {
 	R, G, B uint8
 }
 
 // Palette represents a palette
 type Palette struct {
-	Name   string
+	Name   Palettes.Palette
 	Colors [256]PaletteRGB
 }
 
 // CreatePalette creates a palette
-func CreatePalette(name string, data []byte) Palette {
+func CreatePalette(name Palettes.Palette, data []byte) Palette {
 	result := Palette{Name: name}
 
 	for i := 0; i <= 255; i++ {
diff --git a/Palettes/Palettes.go b/Palettes/Palettes.go
new file mode 100644
index 00000000..577f3fe4
--- /dev/null
+++ b/Palettes/Palettes.go
@@ -0,0 +1,43 @@
+package Palettes
+
+// Palette represents a named palette
+type Palette string
+
+const (
+	// Act1 palette
+	Act1 Palette = "act1"
+	// Act2 palette
+	Act2 Palette = "act2"
+	// Act3 palette
+	Act3 Palette = "act3"
+	// Act4 palette
+	Act4 Palette = "act4"
+	// Act5 palette
+	Act5 Palette = "act5"
+	// EndGame palette
+	EndGame Palette = "endgame"
+	// EndGame2 palette
+	EndGame2 Palette = "endgame2"
+	// Fechar palette
+	Fechar Palette = "fechar"
+	// Loading palette
+	Loading Palette = "loading"
+	// Menu0 palette
+	Menu0 Palette = "menu0"
+	// Menu1 palette
+	Menu1 Palette = "menu1"
+	// Menu2 palette
+	Menu2 Palette = "menu2"
+	// Menu3 palette
+	Menu3 Palette = "menu3"
+	// Menu4 palette
+	Menu4 Palette = "menu4"
+	// Sky palette
+	Sky Palette = "sky"
+	// Static palette
+	Static Palette = "static"
+	// Trademark palette
+	Trademark Palette = "trademark"
+	// Units palette
+	Units Palette = "units"
+)
diff --git a/SceneMainMenu.go b/SceneMainMenu.go
index fdc8ee2a..63a21f58 100644
--- a/SceneMainMenu.go
+++ b/SceneMainMenu.go
@@ -3,119 +3,127 @@ package OpenDiablo2
 import (
 	"image/color"
 
+	"github.com/essial/OpenDiablo2/Palettes"
+
 	"github.com/essial/OpenDiablo2/ResourcePaths"
 	"github.com/hajimehoshi/ebiten"
 )
 
+// MainMenu represents the main menu
 type MainMenu struct {
-	Engine              *Engine
-	TrademarkBackground Sprite
-	Background          Sprite
-	DiabloLogoLeft      Sprite
-	DiabloLogoRight     Sprite
-	DiabloLogoLeftBack  Sprite
-	DiabloLogoRightBack Sprite
-	CopyrightLabel      *UILabel
-	CopyrightLabel2     *UILabel
-	ShowTrademarkScreen bool
-	LeftButtonHeld      bool
+	engine              *Engine
+	trademarkBackground *Sprite
+	background          *Sprite
+	diabloLogoLeft      *Sprite
+	diabloLogoRight     *Sprite
+	diabloLogoLeftBack  *Sprite
+	diabloLogoRightBack *Sprite
+	copyrightLabel      *UILabel
+	copyrightLabel2     *UILabel
+	showTrademarkScreen bool
+	leftButtonHeld      bool
 }
 
+// CreateMainMenu creates an instance of MainMenu
 func CreateMainMenu(engine *Engine) *MainMenu {
 	result := &MainMenu{
-		Engine:              engine,
-		ShowTrademarkScreen: true,
+		engine:              engine,
+		showTrademarkScreen: true,
 	}
 
 	return result
 }
 
+// Load is called to load the resources for the main menu
 func (v *MainMenu) Load() {
-	v.Engine.PlayBGM(ResourcePaths.BGMTitle)
+	v.engine.PlayBGM(ResourcePaths.BGMTitle)
 	go func() {
 		loadStep := 1.0 / 8.0
-		v.Engine.LoadingProgress = 0
+		v.engine.LoadingProgress = 0
 		{
-			v.CopyrightLabel = CreateUILabel(v.Engine, ResourcePaths.FontFormal12, "static")
-			v.CopyrightLabel.Alignment = UILabelAlignCenter
-			v.CopyrightLabel.SetText("Diablo 2 is © Copyright 2000-2016 Blizzard Entertainment")
-			v.CopyrightLabel.ColorMod = color.RGBA{188, 168, 140, 255}
-			v.CopyrightLabel.MoveTo(400, 500)
-			v.Engine.LoadingProgress += loadStep
+			v.copyrightLabel = CreateUILabel(v.engine, ResourcePaths.FontFormal12, Palettes.Static)
+			v.copyrightLabel.Alignment = UILabelAlignCenter
+			v.copyrightLabel.SetText("Diablo 2 is © Copyright 2000-2016 Blizzard Entertainment")
+			v.copyrightLabel.ColorMod = color.RGBA{188, 168, 140, 255}
+			v.copyrightLabel.MoveTo(400, 500)
+			v.engine.LoadingProgress += loadStep
 		}
 		{
-			v.CopyrightLabel2 = CreateUILabel(v.Engine, ResourcePaths.FontFormal12, "static")
-			v.CopyrightLabel2.Alignment = UILabelAlignCenter
-			v.CopyrightLabel2.SetText("All Rights Reserved.")
-			v.CopyrightLabel2.ColorMod = color.RGBA{188, 168, 140, 255}
-			v.CopyrightLabel2.MoveTo(400, 525)
-			v.Engine.LoadingProgress += loadStep
+			v.copyrightLabel2 = CreateUILabel(v.engine, ResourcePaths.FontFormal12, Palettes.Static)
+			v.copyrightLabel2.Alignment = UILabelAlignCenter
+			v.copyrightLabel2.SetText("All Rights Reserved.")
+			v.copyrightLabel2.ColorMod = color.RGBA{188, 168, 140, 255}
+			v.copyrightLabel2.MoveTo(400, 525)
+			v.engine.LoadingProgress += loadStep
 		}
 		{
-			v.Background = v.Engine.LoadSprite(ResourcePaths.GameSelectScreen, v.Engine.Palettes["sky"])
-			v.Background.MoveTo(0, 0)
-			v.Engine.LoadingProgress += loadStep
+			v.background = v.engine.LoadSprite(ResourcePaths.GameSelectScreen, Palettes.Sky)
+			v.background.MoveTo(0, 0)
+			v.engine.LoadingProgress += loadStep
 		}
 		{
-			v.TrademarkBackground = v.Engine.LoadSprite(ResourcePaths.TrademarkScreen, v.Engine.Palettes["sky"])
-			v.TrademarkBackground.MoveTo(0, 0)
-			v.Engine.LoadingProgress += loadStep
+			v.trademarkBackground = v.engine.LoadSprite(ResourcePaths.TrademarkScreen, Palettes.Sky)
+			v.trademarkBackground.MoveTo(0, 0)
+			v.engine.LoadingProgress += loadStep
 		}
 		{
-			v.DiabloLogoLeft = v.Engine.LoadSprite(ResourcePaths.Diablo2LogoFireLeft, v.Engine.Palettes["units"])
-			v.DiabloLogoLeft.Blend = true
-			v.DiabloLogoLeft.Animate = true
-			v.DiabloLogoLeft.MoveTo(400, 120)
-			v.Engine.LoadingProgress += loadStep
+			v.diabloLogoLeft = v.engine.LoadSprite(ResourcePaths.Diablo2LogoFireLeft, Palettes.Units)
+			v.diabloLogoLeft.Blend = true
+			v.diabloLogoLeft.Animate = true
+			v.diabloLogoLeft.MoveTo(400, 120)
+			v.engine.LoadingProgress += loadStep
 		}
 		{
-			v.DiabloLogoRight = v.Engine.LoadSprite(ResourcePaths.Diablo2LogoFireRight, v.Engine.Palettes["units"])
-			v.DiabloLogoRight.Blend = true
-			v.DiabloLogoRight.Animate = true
-			v.DiabloLogoRight.MoveTo(400, 120)
-			v.Engine.LoadingProgress += loadStep
+			v.diabloLogoRight = v.engine.LoadSprite(ResourcePaths.Diablo2LogoFireRight, Palettes.Units)
+			v.diabloLogoRight.Blend = true
+			v.diabloLogoRight.Animate = true
+			v.diabloLogoRight.MoveTo(400, 120)
+			v.engine.LoadingProgress += loadStep
 		}
 		{
-			v.DiabloLogoLeftBack = v.Engine.LoadSprite(ResourcePaths.Diablo2LogoBlackLeft, v.Engine.Palettes["units"])
-			v.DiabloLogoLeftBack.MoveTo(400, 120)
-			v.Engine.LoadingProgress += loadStep
+			v.diabloLogoLeftBack = v.engine.LoadSprite(ResourcePaths.Diablo2LogoBlackLeft, Palettes.Units)
+			v.diabloLogoLeftBack.MoveTo(400, 120)
+			v.engine.LoadingProgress += loadStep
 		}
 		{
-			v.DiabloLogoRightBack = v.Engine.LoadSprite(ResourcePaths.Diablo2LogoBlackRight, v.Engine.Palettes["units"])
-			v.DiabloLogoRightBack.MoveTo(400, 120)
-			v.Engine.LoadingProgress = 1.0
+			v.diabloLogoRightBack = v.engine.LoadSprite(ResourcePaths.Diablo2LogoBlackRight, Palettes.Units)
+			v.diabloLogoRightBack.MoveTo(400, 120)
+			v.engine.LoadingProgress = 1.0
 		}
 	}()
 }
 
+// Unload unloads the data for the main menu
 func (v *MainMenu) Unload() {
 
 }
 
+// Render renders the main menu
 func (v *MainMenu) Render(screen *ebiten.Image) {
-	if v.ShowTrademarkScreen {
-		v.TrademarkBackground.DrawSegments(screen, 4, 3, 0)
+	if v.showTrademarkScreen {
+		v.trademarkBackground.DrawSegments(screen, 4, 3, 0)
 	} else {
-		v.Background.DrawSegments(screen, 4, 3, 0)
+		v.background.DrawSegments(screen, 4, 3, 0)
 	}
-	v.DiabloLogoLeftBack.Draw(screen)
-	v.DiabloLogoRightBack.Draw(screen)
-	v.DiabloLogoLeft.Draw(screen)
-	v.DiabloLogoRight.Draw(screen)
+	v.diabloLogoLeftBack.Draw(screen)
+	v.diabloLogoRightBack.Draw(screen)
+	v.diabloLogoLeft.Draw(screen)
+	v.diabloLogoRight.Draw(screen)
 
-	if v.ShowTrademarkScreen {
-		v.CopyrightLabel.Draw(screen)
-		v.CopyrightLabel2.Draw(screen)
+	if v.showTrademarkScreen {
+		v.copyrightLabel.Draw(screen)
+		v.copyrightLabel2.Draw(screen)
 	} else {
 
 	}
 }
 
+// Update runs the update logic on the main menu
 func (v *MainMenu) Update() {
-	if v.ShowTrademarkScreen {
-		if v.Engine.CursorButtonPressed(CursorButtonLeft) {
-			v.LeftButtonHeld = true
-			v.ShowTrademarkScreen = false
+	if v.showTrademarkScreen {
+		if v.engine.CursorButtonPressed(CursorButtonLeft) {
+			v.leftButtonHeld = true
+			v.showTrademarkScreen = false
 		}
 		return
 	}
diff --git a/Sprite.go b/Sprite.go
index 7ac563fa..3e404759 100644
--- a/Sprite.go
+++ b/Sprite.go
@@ -8,6 +8,7 @@ import (
 	"github.com/hajimehoshi/ebiten"
 )
 
+// Sprite represents a type of object in D2 that is comprised of one or more frames and directions
 type Sprite struct {
 	Directions         uint32
 	FramesPerDirection uint32
@@ -18,8 +19,10 @@ type Sprite struct {
 	LastFrameTime      time.Time
 	Animate            bool
 	ColorMod           color.Color
+	visible            bool
 }
 
+// SpriteFrame represents a single frame of a sprite
 type SpriteFrame struct {
 	Flip      uint32
 	Width     uint32
@@ -33,8 +36,9 @@ type SpriteFrame struct {
 	Image     *ebiten.Image
 }
 
-func CreateSprite(data []byte, palette Palette) Sprite {
-	result := Sprite{
+// CreateSprite creates an instance of a sprite
+func CreateSprite(data []byte, palette Palette) *Sprite {
+	result := &Sprite{
 		X:                  50,
 		Y:                  50,
 		Frame:              0,
@@ -121,6 +125,7 @@ func CreateSprite(data []byte, palette Palette) Sprite {
 	return result
 }
 
+// GetSize returns the size of the sprite
 func (v *Sprite) GetSize() (uint32, uint32) {
 	frame := v.Frames[uint32(v.Frame)+(uint32(v.Direction)*v.FramesPerDirection)]
 	return frame.Width, frame.Height
@@ -159,6 +164,7 @@ func (v *Sprite) Draw(target *ebiten.Image) {
 	target.DrawImage(frame.Image, opts)
 }
 
+// DrawSegments draws the sprite via a grid of segments
 func (v *Sprite) DrawSegments(target *ebiten.Image, xSegments, ySegments, offset int) {
 	v.updateAnimation()
 	yOffset := int32(0)
@@ -191,3 +197,8 @@ func (v *Sprite) MoveTo(x, y int) {
 	v.X = x
 	v.Y = y
 }
+
+// GetLocation returns the location of the sprite
+func (v *Sprite) GetLocation() (int, int) {
+	return v.X, v.Y
+}
diff --git a/UI/Button.go b/UI/Button.go
new file mode 100644
index 00000000..40a60f41
--- /dev/null
+++ b/UI/Button.go
@@ -0,0 +1,8 @@
+package UI
+
+// Button defines an object that acts like a button
+type Button interface {
+	Widget
+	isPressed() bool
+	setPressed(bool)
+}
diff --git a/UI/Widget.go b/UI/Widget.go
new file mode 100644
index 00000000..0f032b54
--- /dev/null
+++ b/UI/Widget.go
@@ -0,0 +1,12 @@
+package UI
+
+import (
+	"github.com/essial/OpenDiablo2/Common"
+)
+
+// Widget defines an object that is a UI widget
+type Widget interface {
+	Common.Drawable
+	getEnabled() bool
+	setEnabled(bool)
+}
diff --git a/UILabel.go b/UILabel.go
index 162de468..072388e6 100644
--- a/UILabel.go
+++ b/UILabel.go
@@ -3,6 +3,7 @@ package OpenDiablo2
 import (
 	"image/color"
 
+	"github.com/essial/OpenDiablo2/Palettes"
 	"github.com/hajimehoshi/ebiten"
 )
 
@@ -27,7 +28,7 @@ type UILabel struct {
 }
 
 // CreateUILabel creates a new instance of a UI label
-func CreateUILabel(engine *Engine, font, palette string) *UILabel {
+func CreateUILabel(engine *Engine, font string, palette Palettes.Palette) *UILabel {
 	result := &UILabel{
 		Alignment: UILabelAlignLeft,
 		ColorMod:  nil,