diff --git a/packages/webamp-modern-2/src/UIRoot.ts b/packages/webamp-modern-2/src/UIRoot.ts
index 29dfe94e..ca009f06 100644
--- a/packages/webamp-modern-2/src/UIRoot.ts
+++ b/packages/webamp-modern-2/src/UIRoot.ts
@@ -5,6 +5,7 @@ import { assert, assume } from "./utils";
 import BitmapFont from "./skin/BitmapFont";
 import Color from "./skin/Color";
 import AUDIO_PLAYER from "./skin/AudioPlayer";
+import GammaGroup from "./skin/GammaGroup";
 
 class UIRoot {
   // Just a temporary place to stash things
@@ -13,6 +14,7 @@ class UIRoot {
   _fonts: (TrueTypeFont | BitmapFont)[] = [];
   _colors: Color[] = [];
   _groupDefs: XmlElement[] = [];
+  _gammaSets: Map<string, GammaGroup[]> = new Map();
   _xuiElements: XmlElement[] = [];
 
   addBitmap(bitmap: Bitmap) {
@@ -52,13 +54,15 @@ class UIRoot {
     return found;
   }
 
-  getFont(id: string): TrueTypeFont | BitmapFont {
+  getFont(id: string): TrueTypeFont | BitmapFont | null {
     const found = this._fonts.find(
       (font) => font.getId().toLowerCase() === id.toLowerCase()
     );
 
-    assert(found != null, `Could not find true type font with id ${id}.`);
-    return found;
+    if (found == null) {
+      console.warn(`Could not find true type font with id ${id}.`);
+    }
+    return found ?? null;
   }
 
   addGroupDef(groupDef: XmlElement) {
@@ -77,6 +81,21 @@ class UIRoot {
     return found ?? null;
   }
 
+  addGammaSet(id: string, gammaSet: GammaGroup[]) {
+    this._gammaSets.set(id.toLowerCase(), gammaSet);
+  }
+
+  getGammaSet(id: string): GammaGroup[] {
+    const found = this._gammaSets.get(id.toLowerCase());
+    assume(
+      found != null,
+      `Could not find gammaset for id "${id}" from set of ${Array.from(
+        this._gammaSets.keys()
+      ).join(", ")}`
+    );
+    return found;
+  }
+
   getXuiElement(name: string): XmlElement | null {
     const lowercaseName = name.toLowerCase();
     const found = this._xuiElements.find(
diff --git a/packages/webamp-modern-2/src/index.ts b/packages/webamp-modern-2/src/index.ts
index ff0b5afa..80ae678e 100644
--- a/packages/webamp-modern-2/src/index.ts
+++ b/packages/webamp-modern-2/src/index.ts
@@ -2,6 +2,8 @@ import JSZip from "jszip";
 // This module is imported early here in order to avoid a circular dependency.
 import { classResolver } from "./skin/resolver";
 import SkinParser from "./skin/parse";
+import UI_ROOT from "./UIRoot";
+import GammaGroup from "./skin/GammaGroup";
 
 function hack() {
   // Without this Snowpack will try to treeshake out resolver causing a circular
@@ -27,13 +29,55 @@ async function main() {
     node.appendChild(container.getDiv());
   }
 
+  const gammaSet = UI_ROOT.getGammaSet("clean | orange (default)");
+
+  const div = document.createElement("div");
+  div.innerHTML = makeGammaSetSVG(gammaSet);
+  document.body.appendChild(div);
+
   document.body.appendChild(node);
   console.log("RENDER");
 
+  window.color = function (name = "clean | lightblue") {
+    const gammaSet = UI_ROOT.getGammaSet(name);
+
+    div.innerHTML = makeGammaSetSVG(gammaSet);
+  };
+
   for (const container of parser._containers) {
     container.init({ containers: parser._containers });
   }
   console.log("INIT");
 }
 
+function makeGammaSetSVG(gammaSet: GammaGroup[]) {
+  // 4000,510,-4000
+  return `<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 600 300">
+  <defs>
+    ${gammaSet.map((group) => makeGammaGroupSVG(group)).join("\n")}
+  </defs>
+</svg>`;
+}
+
+function colorToFrac(num: string) {
+  // -4096 to 4096
+  return Number(num) / 4096;
+}
+
+// https://webplatform.github.io/docs/svg/elements/feFuncA/
+// amplitude * pow(C, exponent) + offset (see below for amplitude, exponent, and offset)
+// https://www.pawelporwisz.pl/winamp/wct_en.php
+// TODO: Avoid XSS
+function makeGammaGroupSVG(gammaGroup: GammaGroup) {
+  const [r, g, b] = gammaGroup._value.split(",").map(colorToFrac);
+  return `<filter id="${gammaGroup.getDomId()}" x="0" y="0" width="100%" height="100%">
+  <feComponentTransfer>
+    <feFuncR type="gamma" amplitude="1" exponent="1" offset="${r}" />
+    <feFuncG type="gamma" amplitude="1" exponent="1" offset="${g}" />
+    <feFuncB type="gamma" amplitude="1" exponent="1" offset="${b}" />
+    
+  </feComponentTransfer>
+</filter>`;
+}
+
 main();
diff --git a/packages/webamp-modern-2/src/maki/interpreter.tsx b/packages/webamp-modern-2/src/maki/interpreter.tsx
index 1e765672..a5ba23e3 100644
--- a/packages/webamp-modern-2/src/maki/interpreter.tsx
+++ b/packages/webamp-modern-2/src/maki/interpreter.tsx
@@ -564,11 +564,6 @@ class Interpreter {
         // ! (not)
         case 74: {
           const a = this.stack.pop();
-          switch (a.type) {
-            case "STRING":
-            case "OBJECT":
-              throw new Error("Tried ! a string or object.");
-          }
           this.push(V.newInt(!a.value));
           break;
         }
diff --git a/packages/webamp-modern-2/src/skin/Bitmap.ts b/packages/webamp-modern-2/src/skin/Bitmap.ts
index 3126b74d..e133cbc9 100644
--- a/packages/webamp-modern-2/src/skin/Bitmap.ts
+++ b/packages/webamp-modern-2/src/skin/Bitmap.ts
@@ -1,8 +1,10 @@
 import * as Utils from "../utils";
-import { assert } from "../utils";
+import { assert, getId } from "../utils";
 import ImageManager from "./ImageManager";
 
+// http://wiki.winamp.com/wiki/XML_Elements#.3Cbitmap.2F.3E
 export default class Bitmap {
+  _uniqueId: number = getId();
   _id: string;
   _url: string;
   _img: HTMLImageElement;
@@ -61,7 +63,14 @@ export default class Bitmap {
     return this._height;
   }
 
+  getCSSVar(): string {
+    return `--bitmap-${this.getId().replace(/[^a-zA-Z0-9]/g, "-")}-${
+      this._uniqueId
+    }`;
+  }
+
   setUrl(url: string) {
+    document.documentElement.style.setProperty(this.getCSSVar(), `url(${url})`);
     this._url = url;
   }
 
@@ -85,7 +94,7 @@ export default class Bitmap {
   }
 
   getBackgrondImageCSSAttribute(): string {
-    return `url(${this._url})`;
+    return `var(${this.getCSSVar()})`;
   }
 
   getBackgrondPositionCSSAttribute(): string {
@@ -100,6 +109,10 @@ export default class Bitmap {
     return `${width} ${height}`;
   }
 
+  getBackdropFilterCSSAttribute(): string {
+    return `url(#${Utils.normalizeDomId(this._gammagroup)})`;
+  }
+
   getCanvas(): HTMLCanvasElement {
     if (this._canvas == null) {
       assert(this._img != null, "Expected bitmap image to be loaded");
diff --git a/packages/webamp-modern-2/src/skin/Button.ts b/packages/webamp-modern-2/src/skin/Button.ts
index 474b0624..c1489e3c 100644
--- a/packages/webamp-modern-2/src/skin/Button.ts
+++ b/packages/webamp-modern-2/src/skin/Button.ts
@@ -77,11 +77,15 @@ export default class Button extends GuiObj {
     if (this._image != null) {
       const bitmap = UI_ROOT.getBitmap(this._image);
       this.setBackgroundImage(bitmap);
+    } else {
+      this.setBackgroundImage(null);
     }
 
     if (this._downimage != null) {
       const downBitmap = UI_ROOT.getBitmap(this._downimage);
       this.setActiveBackgroundImage(downBitmap);
+    } else {
+      this.setActiveBackgroundImage(null);
     }
   }
 
diff --git a/packages/webamp-modern-2/src/skin/GammaGroup.ts b/packages/webamp-modern-2/src/skin/GammaGroup.ts
new file mode 100644
index 00000000..96eb0b21
--- /dev/null
+++ b/packages/webamp-modern-2/src/skin/GammaGroup.ts
@@ -0,0 +1,46 @@
+import { normalizeDomId, num, toBool } from "../utils";
+
+export default class GammaGroup {
+  _id: string;
+  _value: string;
+  _boost: number = 0;
+  _gray: number = 0;
+
+  setXmlAttributes(attributes: { [attrName: string]: string }) {
+    for (const [key, value] of Object.entries(attributes)) {
+      this.setXmlAttr(key, value);
+    }
+  }
+
+  setXmlAttr(_key: string, value: string) {
+    const key = _key.toLowerCase();
+    switch (key) {
+      case "id":
+        this._id = value;
+        break;
+      case "value":
+        this._value = value;
+        break;
+      case "boost":
+        this._boost = num(value);
+        break;
+      case "gray":
+        this._gray = num(value);
+      default:
+        return false;
+    }
+    return true;
+  }
+
+  getId() {
+    return this._id;
+  }
+
+  getDomId() {
+    return normalizeDomId(this._id);
+  }
+
+  getRgb() {
+    return `rgb(${this._value})`;
+  }
+}
diff --git a/packages/webamp-modern-2/src/skin/Group.ts b/packages/webamp-modern-2/src/skin/Group.ts
index effc904a..ccfa91a9 100644
--- a/packages/webamp-modern-2/src/skin/Group.ts
+++ b/packages/webamp-modern-2/src/skin/Group.ts
@@ -117,8 +117,9 @@ export default class Group extends GuiObj {
     if (this._background != null && this._drawBackground) {
       const bitmap = UI_ROOT.getBitmap(this._background);
       this.setBackgroundImage(bitmap);
+    } else {
+      this.setBackgroundImage(null);
     }
-    // TODO: Clear background
   }
 
   draw() {
diff --git a/packages/webamp-modern-2/src/skin/GuiObj.ts b/packages/webamp-modern-2/src/skin/GuiObj.ts
index 2335cbb3..06bebc94 100644
--- a/packages/webamp-modern-2/src/skin/GuiObj.ts
+++ b/packages/webamp-modern-2/src/skin/GuiObj.ts
@@ -217,6 +217,22 @@ export default class GuiObj extends XmlObj {
     ]);
   }
 
+  /**
+   * Hookable. Event happens when the mouse
+   * enters the objects area.
+   */
+  onEnterArea() {
+    VM.dispatch(this, "onenterarea");
+  }
+
+  /**
+   * Hookable. Event happens when the mouse
+   * leaves the objects area.
+   */
+  onLeaveArea() {
+    VM.dispatch(this, "onleavearea");
+  }
+
   /**
    * Set a target X position, in the screen, for
    * the object.
@@ -359,28 +375,29 @@ export default class GuiObj extends XmlObj {
     this._renderHeight();
   }
 
-  setBackgroundImage(bitmap: Bitmap) {
+  setBackgroundImage(bitmap: Bitmap | null) {
     this._div.style.setProperty(
       "--background-image",
-      bitmap.getBackgrondImageCSSAttribute()
+      bitmap?.getBackgrondImageCSSAttribute() ?? "none"
     );
     this._div.style.setProperty(
       "--background-position",
-      bitmap.getBackgrondPositionCSSAttribute()
+      bitmap?.getBackgrondPositionCSSAttribute() ?? "none"
     );
+    this._div.style.filter = bitmap?.getBackdropFilterCSSAttribute() ?? "none";
   }
 
   // JS Can't set the :active pseudo selector. Instead we have a hard-coded
   // pseduo-selector in our stylesheet which references a CSS variable and then
   // we control the value of that variable from JS.
-  setActiveBackgroundImage(bitmap: Bitmap) {
+  setActiveBackgroundImage(bitmap: Bitmap | null) {
     this._div.style.setProperty(
       "--active-background-image",
-      bitmap.getBackgrondImageCSSAttribute()
+      bitmap?.getBackgrondImageCSSAttribute() ?? "none"
     );
     this._div.style.setProperty(
       "--active-background-position",
-      bitmap.getBackgrondPositionCSSAttribute()
+      bitmap?.getBackgrondPositionCSSAttribute() ?? "none"
     );
   }
 
@@ -406,5 +423,12 @@ export default class GuiObj extends XmlObj {
     this._div.addEventListener("mousedown", (e) => {
       this.onLeftButtonDown(e.clientX, e.clientY);
     });
+    this._div.addEventListener("mouseenter", (e) => {
+      this.onEnterArea();
+    });
+
+    this._div.addEventListener("mouseleave", (e) => {
+      this.onLeaveArea();
+    });
   }
 }
diff --git a/packages/webamp-modern-2/src/skin/Slider.ts b/packages/webamp-modern-2/src/skin/Slider.ts
index 977e579d..0badc15d 100644
--- a/packages/webamp-modern-2/src/skin/Slider.ts
+++ b/packages/webamp-modern-2/src/skin/Slider.ts
@@ -1,5 +1,5 @@
 import UI_ROOT from "../UIRoot";
-import { clamp, num, px } from "../utils";
+import { assume, clamp, num, px } from "../utils";
 import GuiObj from "./GuiObj";
 import { VM } from "./VM";
 
@@ -129,8 +129,6 @@ export default class Slider extends GuiObj {
       const startX = rect.x;
       const startY = rect.y;
       const width = this.getwidth();
-      const startMouseX = downEvent.clientX;
-      const startMouseY = downEvent.clientY;
 
       const handleMove = (moveEvent: MouseEvent) => {
         const newMouseX = moveEvent.clientX;
@@ -138,16 +136,23 @@ export default class Slider extends GuiObj {
         const deltaX = newMouseX - startX;
         const deltaY = newMouseY - startY;
 
+        // TODO: What about vertical sliders?
         const xPos = clamp(deltaX, 0, width);
         this._position = xPos / width;
         this._renderThumbPosition();
         this.onsetposition(this.getposition());
       };
 
-      function handleMouseUp() {
+      const handleMouseUp = () => {
+        VM.dispatch(this, "onsetfinalposition", [
+          { type: "INT", value: this.getposition() },
+        ]);
+        VM.dispatch(this, "onpostedposition", [
+          { type: "INT", value: this.getposition() },
+        ]);
         document.removeEventListener("mousemove", handleMove);
         document.removeEventListener("mouseup", handleMouseUp);
-      }
+      };
       document.addEventListener("mousemove", handleMove);
       document.addEventListener("mouseup", handleMouseUp);
     });
@@ -156,6 +161,9 @@ export default class Slider extends GuiObj {
   draw() {
     super.draw();
     this._div.setAttribute("data-obj-name", "Slider");
+    assume(this._barLeft == null, "Need to handle Slider barleft");
+    assume(this._barRight == null, "Need to handle Slider barright");
+    assume(this._barMiddle == null, "Need to handle Slider barmiddle");
     this._renderThumb();
     this._renderThumbPosition();
     this._div.appendChild(this._thumbDiv);
diff --git a/packages/webamp-modern-2/src/skin/Text.ts b/packages/webamp-modern-2/src/skin/Text.ts
index c975844f..ed353b26 100644
--- a/packages/webamp-modern-2/src/skin/Text.ts
+++ b/packages/webamp-modern-2/src/skin/Text.ts
@@ -94,7 +94,11 @@ offsety - (int) Extra pixels to be added to or subtracted from the calculated x
 
   getText() {
     if (this._display) {
-      switch (this._display) {
+      switch (this._display.toLowerCase()) {
+        case "pe_info":
+          return "pe_info";
+        case "vid_info":
+          return "vid_info";
         case "time":
           return "01:58";
         case "songlength":
@@ -140,6 +144,9 @@ offsety - (int) Extra pixels to be added to or subtracted from the calculated x
         }
 
         //
+      } else if (font == null) {
+        this._div.innerText = this.getText();
+        this._div.style.fontFamily = "Ariel";
       } else {
         throw new Error("Unexpected font");
       }
diff --git a/packages/webamp-modern-2/src/skin/parse.ts b/packages/webamp-modern-2/src/skin/parse.ts
index 0f3e8e89..50150555 100644
--- a/packages/webamp-modern-2/src/skin/parse.ts
+++ b/packages/webamp-modern-2/src/skin/parse.ts
@@ -21,6 +21,7 @@ import AnimatedLayer from "./AnimatedLayer";
 import Vis from "./Vis";
 import BitmapFont from "./BitmapFont";
 import Color from "./Color";
+import GammaGroup from "./GammaGroup";
 
 class ParserContext {
   container: Container | null = null;
@@ -33,6 +34,7 @@ export default class SkinParser {
   _path: string[] = [];
   _context: ParserContext = new ParserContext();
   _containers: Container[] = [];
+  _gammaSet: GammaGroup[] = [];
 
   constructor(zip: JSZip) {
     this._zip = zip;
@@ -409,11 +411,19 @@ export default class SkinParser {
   }
 
   async gammaset(node: XmlElement) {
+    this._gammaSet = [];
     await this.traverseChildren(node);
+    UI_ROOT.addGammaSet(node.attributes.id, this._gammaSet);
   }
 
   async gammagroup(node: XmlElement) {
-    await this.traverseChildren(node);
+    assume(
+      node.children.length === 0,
+      "Unexpected children in <gammagroup> XML node."
+    );
+    const gammaGroup = new GammaGroup();
+    gammaGroup.setXmlAttributes(node.attributes);
+    this._gammaSet.push(gammaGroup);
   }
 
   async component(node: XmlElement) {
diff --git a/packages/webamp-modern-2/src/utils.ts b/packages/webamp-modern-2/src/utils.ts
index af0988a4..0ef24cf5 100644
--- a/packages/webamp-modern-2/src/utils.ts
+++ b/packages/webamp-modern-2/src/utils.ts
@@ -31,7 +31,10 @@ export function px(size: number): string {
 }
 
 export function toBool(str: string) {
-  assert(str === "0" || str === "1", 'Expected bool value to be "0" or "1".');
+  assert(
+    str === "0" || str === "1",
+    `Expected bool value to be "0" or "1", but it was "${str}".`
+  );
   return str === "1";
 }
 
@@ -48,3 +51,7 @@ export function ensureVmInt(num: number): number {
 export function clamp(num: number, min: number, max: number): number {
   return Math.max(min, Math.min(num, max));
 }
+
+export function normalizeDomId(id: string) {
+  return id.replace(/[^a-zA-Z0-9]/g, "-");
+}