diff --git a/core/src/avm1.rs b/core/src/avm1.rs
index fa5ae180b..7be79f764 100644
--- a/core/src/avm1.rs
+++ b/core/src/avm1.rs
@@ -1433,11 +1433,13 @@ impl<'gc> Avm1<'gc> {
 
         let constructor = object
             .read()
-            .get(&method_name.as_string()?, self, context, object.to_owned())
+            .get(&method_name.as_string()?, self, context, object.to_owned())?
+            .resolve(self, context)?
             .as_object()?;
         let proto = constructor
             .read()
-            .get("prototype", self, context, constructor.to_owned());
+            .get("prototype", self, context, constructor.to_owned())?
+            .resolve(self, context)?;
         let this = GcCell::allocate(
             context.gc_context,
             Object::object(
@@ -1447,7 +1449,10 @@ impl<'gc> Avm1<'gc> {
         );
 
         //TODO: What happens if you `ActionNewMethod` without a method name?
-        constructor.read().call(self, context, this, &args);
+        constructor
+            .read()
+            .call(self, context, this, &args)?
+            .ignore();
 
         //TODO: The SWF docs are really cagey about what the hell happens with
         //user defined constructors... do we need stack continuations?!
@@ -1470,11 +1475,13 @@ impl<'gc> Avm1<'gc> {
             .unwrap()
             .clone()
             .read()
-            .resolve(fn_name.as_string()?, self, context)
+            .resolve(fn_name.as_string()?, self, context)?
+            .resolve(self, context)?
             .as_object()?;
         let proto = constructor
             .read()
-            .get("prototype", self, context, constructor.to_owned());
+            .get("prototype", self, context, constructor.to_owned())?
+            .resolve(self, context)?;
         let this = GcCell::allocate(
             context.gc_context,
             Object::object(
@@ -1483,7 +1490,10 @@ impl<'gc> Avm1<'gc> {
             ),
         );
 
-        constructor.read().call(self, context, this, &args);
+        constructor
+            .read()
+            .call(self, context, this, &args)?
+            .ignore();
 
         self.push(Value::Undefined);
 
diff --git a/core/src/avm1/globals/object.rs b/core/src/avm1/globals/object.rs
index 9d6ac1d06..bc4558dad 100644
--- a/core/src/avm1/globals/object.rs
+++ b/core/src/avm1/globals/object.rs
@@ -12,7 +12,7 @@ pub fn add_property<'gc>(
     context: &mut UpdateContext<'_, 'gc, '_>,
     this: GcCell<'gc, Object<'gc>>,
     args: &[Value<'gc>],
-) -> Value<'gc> {
+) -> Result<ReturnValue<'gc>, Error> {
     let name = args.get(0).unwrap_or(&Value::Undefined);
     let getter = args.get(1).unwrap_or(&Value::Undefined);
     let setter = args.get(2).unwrap_or(&Value::Undefined);
@@ -29,19 +29,19 @@ pub fn add_property<'gc>(
                             EnumSet::empty(),
                         );
                     } else {
-                        return Value::Bool(false);
+                        return Ok(false.into());
                     }
                 } else if let Value::Null = setter {
                     this.write(context.gc_context)
                         .force_set_virtual(name, get_func, None, ReadOnly);
                 } else {
-                    return Value::Bool(false);
+                    return Ok(false.into());
                 }
             }
 
-            Value::Bool(false)
+            Ok(false.into())
         }
-        _ => Value::Bool(false),
+        _ => Ok(false.into()),
     }
 }
 
@@ -68,6 +68,46 @@ fn to_string<'gc>(
     Ok(ReturnValue::Immediate("[Object object]".into()))
 }
 
+/// Implements `Object.prototype.isPropertyEnumerable`
+fn is_property_enumerable<'gc>(
+    _: &mut Avm1<'gc>,
+    _: &mut UpdateContext<'_, 'gc, '_>,
+    this: GcCell<'gc, Object<'gc>>,
+    args: &[Value<'gc>],
+) -> Result<ReturnValue<'gc>, Error> {
+    match args.get(0) {
+        Some(Value::String(name)) => {
+            Ok(Value::Bool(this.read().is_property_enumerable(name)).into())
+        }
+        _ => Ok(Value::Bool(false).into()),
+    }
+}
+
+/// Implements `Object.prototype.isPrototypeOf`
+fn is_prototype_of<'gc>(
+    _: &mut Avm1<'gc>,
+    _: &mut UpdateContext<'_, 'gc, '_>,
+    this: GcCell<'gc, Object<'gc>>,
+    args: &[Value<'gc>],
+) -> Result<ReturnValue<'gc>, Error> {
+    match args.get(0) {
+        Some(Value::Object(ob)) => {
+            let mut proto = ob.read().prototype().cloned();
+
+            while let Some(proto_ob) = proto {
+                if GcCell::ptr_eq(this, proto_ob) {
+                    return Ok(Value::Bool(true).into());
+                }
+
+                proto = proto_ob.read().prototype().cloned();
+            }
+
+            Ok(Value::Bool(false).into())
+        }
+        _ => Ok(Value::Bool(false).into()),
+    }
+}
+
 /// Partially construct `Object.prototype`.
 ///
 /// `__proto__` and other cross-linked properties of this object will *not*
@@ -88,14 +128,28 @@ pub fn fill_proto<'gc>(
         "addProperty",
         add_property,
         gc_context,
-        EnumSet::empty(),
+        DontDelete | DontEnum,
         Some(fn_proto),
     );
     ob_proto_write.force_set_function(
         "hasOwnProperty",
         has_own_property,
         gc_context,
-        EnumSet::empty(),
+        DontDelete | DontEnum,
+        Some(fn_proto),
+    );
+    ob_proto_write.force_set_function(
+        "isPropertyEnumerable",
+        is_property_enumerable,
+        gc_context,
+        DontDelete | DontEnum,
+        Some(fn_proto),
+    );
+    ob_proto_write.force_set_function(
+        "isPrototypeOf",
+        is_prototype_of,
+        gc_context,
+        DontDelete | DontEnum,
         Some(fn_proto),
     );
     ob_proto_write.force_set_function(
diff --git a/core/src/avm1/object.rs b/core/src/avm1/object.rs
index a1f75fc5a..07b20e164 100644
--- a/core/src/avm1/object.rs
+++ b/core/src/avm1/object.rs
@@ -389,6 +389,14 @@ impl<'gc> Object<'gc> {
             .unwrap_or(false)
     }
 
+    pub fn is_property_enumerable(&self, name: &str) -> bool {
+        if let Some(prop) = self.values.get(name) {
+            prop.is_enumerable()
+        } else {
+            false
+        }
+    }
+
     pub fn get_keys(&self) -> Vec<String> {
         self.values
             .iter()
@@ -435,7 +443,7 @@ impl<'gc> Object<'gc> {
     /// Returns a copy of a given function.
     ///
     /// TODO: We have to clone here because of how executables are stored on
-    /// objects. This might not be a good idea for performance.
+    /// objects directly. This might not be a good idea for performance.
     pub fn as_executable(&self) -> Option<Executable<'gc>> {
         self.function.clone()
     }