diff --git a/src/js/git/index.js b/src/js/git/index.js
index 2825a96a..7754f2ae 100644
--- a/src/js/git/index.js
+++ b/src/js/git/index.js
@@ -518,7 +518,7 @@ GitEngine.prototype.getOrMakeRecursive = function(
 
   if (type == 'HEAD') {
     var headJSON = tree.HEAD;
-    var HEAD = new Ref(_.extend(
+    var HEAD = new Ref(Object.assign(
       tree.HEAD,
       {
         target: this.getOrMakeRecursive(tree, createdSoFar, headJSON.target)
@@ -531,7 +531,7 @@ GitEngine.prototype.getOrMakeRecursive = function(
   if (type == 'branch') {
     var branchJSON = tree.branches[objID];
 
-    var branch = new Branch(_.extend(
+    var branch = new Branch(Object.assign(
       tree.branches[objID],
       {
         target: this.getOrMakeRecursive(tree, createdSoFar, branchJSON.target)
@@ -544,7 +544,7 @@ GitEngine.prototype.getOrMakeRecursive = function(
   if (type == 'tag') {
     var tagJSON = tree.tags[objID];
 
-    var tag = new Tag(_.extend(
+    var tag = new Tag(Object.assign(
       tree.tags[objID],
       {
         target: this.getOrMakeRecursive(tree, createdSoFar, tagJSON.target)
@@ -563,7 +563,7 @@ GitEngine.prototype.getOrMakeRecursive = function(
       parentObjs.push(this.getOrMakeRecursive(tree, createdSoFar, parentID));
     }, this);
 
-    var commit = new Commit(_.extend(
+    var commit = new Commit(Object.assign(
       commitJSON,
       {
         parents: parentObjs,
@@ -846,7 +846,7 @@ GitEngine.prototype.makeCommit = function(parents, id, options) {
     id = this.getUniqueID();
   }
 
-  var commit = new Commit(_.extend({
+  var commit = new Commit(Object.assign({
       parents: parents,
       id: id,
       gitVisuals: this.gitVisuals
@@ -1284,7 +1284,7 @@ GitEngine.prototype.fetchCore = function(sourceDestPairs, options) {
       this.origin,
       pair.destination,
       pair.source,
-      _.extend(
+      Object.assign(
         {},
         options,
         {dontThrowOnNoFetch: true}
diff --git a/src/js/graph/index.js b/src/js/graph/index.js
index 49285de0..ed2c0745 100644
--- a/src/js/graph/index.js
+++ b/src/js/graph/index.js
@@ -44,7 +44,7 @@ var Graph = {
 
     if (type == 'HEAD') {
       var headJSON = tree.HEAD;
-      var HEAD = new Ref(_.extend(
+      var HEAD = new Ref(Object.assign(
         tree.HEAD,
         {
           target: this.getOrMakeRecursive(tree, createdSoFar, headJSON.target)
@@ -57,7 +57,7 @@ var Graph = {
     if (type == 'branch') {
       var branchJSON = tree.branches[objID];
 
-      var branch = new Branch(_.extend(
+      var branch = new Branch(Object.assign(
         tree.branches[objID],
         {
           target: this.getOrMakeRecursive(tree, createdSoFar, branchJSON.target)
@@ -70,7 +70,7 @@ var Graph = {
     if (type == 'tag') {
       var tagJSON = tree.tags[objID];
 
-      var tag = new Tag(_.extend(
+      var tag = new Tag(Object.assign(
         tree.tags[objID],
         {
           target: this.getOrMakeRecursive(tree, createdSoFar, tagJSON.target)
@@ -89,7 +89,7 @@ var Graph = {
         parentObjs.push(this.getOrMakeRecursive(tree, createdSoFar, parentID));
       }, this);
 
-      var commit = new Commit(_.extend(
+      var commit = new Commit(Object.assign(
         commitJSON,
         {
           parents: parentObjs,
diff --git a/src/js/graph/treeCompare.js b/src/js/graph/treeCompare.js
index 132782bd..75835ab6 100644
--- a/src/js/graph/treeCompare.js
+++ b/src/js/graph/treeCompare.js
@@ -92,7 +92,7 @@ TreeCompare.compareAllBranchesWithinTrees = function(treeA, treeB) {
   treeA = this.convertTreeSafe(treeA);
   treeB = this.convertTreeSafe(treeB);
 
-  var allBranches = _.extend(
+  var allBranches = Object.assign(
     {},
     treeA.branches,
     treeB.branches
@@ -140,7 +140,7 @@ TreeCompare.compareAllBranchesWithinTreesHashAgnostic = function(treeA, treeB) {
   treeB = this.convertTreeSafe(treeB);
   this.reduceTreeFields([treeA, treeB]);
 
-  var allBranches = _.extend(
+  var allBranches = Object.assign(
     {},
     treeA.branches,
     treeB.branches
@@ -270,7 +270,7 @@ TreeCompare.getRecurseCompareHashAgnostic = function(treeA, treeB) {
   // some buildup functions
   var getStrippedCommitCopy = function(commit) {
     if (!commit) { return {}; }
-    return _.extend(
+    return Object.assign(
       {},
       commit,
       {
diff --git a/src/js/level/builder.js b/src/js/level/builder.js
index e823d239..a5a848a6 100644
--- a/src/js/level/builder.js
+++ b/src/js/level/builder.js
@@ -360,7 +360,7 @@ var LevelBuilder = Level.extend({
   },
 
   getExportObj: function() {
-    var compiledLevel = _.extend(
+    var compiledLevel = Object.assign(
       {},
       this.level
     );
diff --git a/src/js/level/index.js b/src/js/level/index.js
index 62b6a364..e2801d6e 100644
--- a/src/js/level/index.js
+++ b/src/js/level/index.js
@@ -70,7 +70,7 @@ var Level = Sandbox.extend({
     // if there is a multiview in the beginning, open that
     // and let it resolve our deferred
     if (this.level.startDialog && !this.testOption('noIntroDialog')) {
-      new MultiView(_.extend(
+      new MultiView(Object.assign(
         {},
         intl.getStartDialog(this.level),
         { deferred: deferred }
@@ -99,7 +99,7 @@ var Level = Sandbox.extend({
     var dialog = $.extend({}, intl.getStartDialog(levelObj));
     // grab the last slide only
     dialog.childViews = dialog.childViews.slice(-1);
-    new MultiView(_.extend(
+    new MultiView(Object.assign(
       dialog,
       { deferred: deferred }
     ));
diff --git a/src/js/sandbox/commands.js b/src/js/sandbox/commands.js
index 6da2b6a6..83a741b0 100644
--- a/src/js/sandbox/commands.js
+++ b/src/js/sandbox/commands.js
@@ -134,7 +134,7 @@ var getAllCommands = function() {
     'mobileAlert'
   ];
 
-  var allCommands = _.extend(
+  var allCommands = Object.assign(
     {},
     require('../level').regexMap,
     regexMap
diff --git a/src/js/views/builderViews.js b/src/js/views/builderViews.js
index bc8cc01d..9d2ba96f 100644
--- a/src/js/views/builderViews.js
+++ b/src/js/views/builderViews.js
@@ -179,7 +179,7 @@ var DemonstrationBuilder = ContainedBase.extend({
     this.deferred = options.deferred || Q.defer();
     if (options.fromObj) {
       var toEdit = options.fromObj.options;
-      options = _.extend(
+      options = Object.assign(
         {},
         options,
         toEdit,
diff --git a/src/js/views/gitDemonstrationView.js b/src/js/views/gitDemonstrationView.js
index 0c088c26..f0fa0810 100644
--- a/src/js/views/gitDemonstrationView.js
+++ b/src/js/views/gitDemonstrationView.js
@@ -25,7 +25,7 @@ var GitDemonstrationView = ContainedBase.extend({
   initialize: function(options) {
     options = options || {};
     this.options = options;
-    this.JSON = _.extend(
+    this.JSON = Object.assign(
       {
         beforeMarkdowns: [
           '## Git Commits',
diff --git a/src/js/views/index.js b/src/js/views/index.js
index b98d034a..7182d2a0 100644
--- a/src/js/views/index.js
+++ b/src/js/views/index.js
@@ -372,7 +372,7 @@ var ConfirmCancelTerminal = Backbone.View.extend({
     options = options || {};
 
     this.deferred = options.deferred || Q.defer();
-    this.modalAlert = new ModalAlert(_.extend(
+    this.modalAlert = new ModalAlert(Object.assign(
       {},
       { markdown: '#you sure?' },
       options
@@ -470,7 +470,7 @@ var NextLevelConfirm = ConfirmCancelTerminal.extend({
         '</p>';
     }
 
-    options = _.extend(
+    options = Object.assign(
       {},
       options,
       {
diff --git a/src/js/views/multiView.js b/src/js/views/multiView.js
index 79ec192b..faffa3d0 100644
--- a/src/js/views/multiView.js
+++ b/src/js/views/multiView.js
@@ -159,7 +159,7 @@ var MultiView = Backbone.View.extend({
     if (!this.typeToConstructor[type]) {
       throw new Error('no constructor for type "' + type + '"');
     }
-    var view = new this.typeToConstructor[type](_.extend(
+    var view = new this.typeToConstructor[type](Object.assign(
       {},
       viewJSON.options,
       { wait: true }
diff --git a/src/js/visuals/tree.js b/src/js/visuals/tree.js
index e5952228..5d9b92dd 100644
--- a/src/js/visuals/tree.js
+++ b/src/js/visuals/tree.js
@@ -13,7 +13,7 @@ var VisBase = Backbone.Model.extend({
   animateAttrKeys: function(keys, attrObj, speed, easing) {
     // either we animate a specific subset of keys or all
     // possible things we could animate
-    keys = _.extend(
+    keys = Object.assign(
       {},
       {
         include: ['circle', 'arrow', 'rect', 'path', 'text'],
@@ -26,7 +26,7 @@ var VisBase = Backbone.Model.extend({
 
     // safely insert this attribute into all the keys we want
     _.each(keys.include, function(key) {
-      attr[key] = _.extend(
+      attr[key] = Object.assign(
         {},
         attr[key],
         attrObj
diff --git a/src/js/visuals/visBase.js b/src/js/visuals/visBase.js
index 92eff1b2..5196a575 100644
--- a/src/js/visuals/visBase.js
+++ b/src/js/visuals/visBase.js
@@ -58,7 +58,7 @@ var VisBase = Backbone.Model.extend({
   animateAttrKeys: function(keys, attrObj, speed, easing) {
     // either we animate a specific subset of keys or all
     // possible things we could animate
-    keys = _.extend(
+    keys = Object.assign(
       {},
       {
         include: ['circle', 'arrow', 'rect', 'path', 'text'],
@@ -71,7 +71,7 @@ var VisBase = Backbone.Model.extend({
 
     // safely insert this attribute into all the keys we want
     _.each(keys.include, function(key) {
-      attr[key] = _.extend(
+      attr[key] = Object.assign(
         {},
         attr[key],
         attrObj
diff --git a/src/js/visuals/visualization.js b/src/js/visuals/visualization.js
index 3ac6b0f4..5cf27cb4 100644
--- a/src/js/visuals/visualization.js
+++ b/src/js/visuals/visualization.js
@@ -104,7 +104,7 @@ var Visualization = Backbone.View.extend({
   makeOrigin: function(options) {
     // oh god, here we go. We basically do a bizarre form of composition here,
     // where this visualization actually contains another one of itself.
-    this.originVis = new Visualization(_.extend(
+    this.originVis = new Visualization(Object.assign(
       {},
       // copy all of our options over, except...
       this.options,