diff --git a/source/engine/2dphysics.c b/source/engine/2dphysics.c
index 694da47..15f6d5b 100644
--- a/source/engine/2dphysics.c
+++ b/source/engine/2dphysics.c
@@ -468,19 +468,19 @@ void phys2d_dbgdrawedge(struct phys2d_edge *edge)
     }
 }
 
-cpShape *id2shape(int id)
+void shape_enabled(struct phys2d_shape *shape, int enabled)
 {
-    return NULL;
+    YughInfo("Setting shape %p to enabled? %d.", shape, enabled);
+    if (enabled)
+      cpSpaceAddShape(space, shape->shape);
+    else
+      cpSpaceRemoveShape(space, shape->shape);
 }
 
-void shape_enable(struct phys2d_shape *shape)
+void shape_set_sensor(struct phys2d_shape *shape, int sensor)
 {
-    cpSpaceAddShape(space, shape->shape);
-}
-
-void shape_disable(struct phys2d_shape *shape)
-{
-    cpSpaceRemoveShape(space, shape->shape);
+    YughInfo("Setting shape %p to sensor? %d.", shape, sensor);
+    cpShapeSetSensor(shape->shape, sensor);
 }
 
 void phys2d_reindex_body(cpBody *body) {
diff --git a/source/engine/2dphysics.h b/source/engine/2dphysics.h
index 2460cf7..d07494f 100644
--- a/source/engine/2dphysics.h
+++ b/source/engine/2dphysics.h
@@ -97,10 +97,8 @@ void phys2d_add_handler_type(int cmd, int go,  struct callee c);
 void register_collide(void *sym);
 void phys2d_set_gravity(cpVect v);
 
-void shape_enable(struct phys2d_shape *shape);
-void shape_disable(struct phys2d_shape *shape);
-
-cpShape *id2shape(int id);
+void shape_enabled(struct phys2d_shape *shape, int enabled);
+void shape_set_sensor(struct phys2d_shape *shape, int sensor);
 
 struct color {
     unsigned char r;
diff --git a/source/engine/ffi.c b/source/engine/ffi.c
index 7ddc927..cb836b4 100644
--- a/source/engine/ffi.c
+++ b/source/engine/ffi.c
@@ -153,30 +153,23 @@ duk_ret_t duk_cmd(duk_context *duk) {
          break;
 
        case 18:
-         cpShapeSetSensor(id2shape(duk_to_int(duk, 1)), duk_to_boolean(duk, 2));
+         shape_set_sensor(duk_to_pointer(duk, 1), duk_to_boolean(duk, 2));
          break;
 
        case 19:
-         if (id2shape(duk_to_int(duk, 1)))
-             duk_push_boolean(duk, cpShapeGetSensor(id2shape(duk_to_int(duk, 1))));
-         else
-             duk_push_undefined(duk);
-
-         return 1;
+         mix_master_vol(duk_to_number(duk, 1));
+         break;
 
        case 20:
          sprite_enabled(duk_to_int(duk, 1), duk_to_boolean(duk, 2));
          break;
 
        case 21:
-         duk_push_boolean(duk, id2sprite(duk_to_int(duk, 1))->enabled);
-         return 1;
+         break;
 
        case 22:
-         return 0;
-
-       case 23:
-         return 0;
+         shape_enabled(duk_to_pointer(duk, 1), duk_to_int(duk, 2));
+         break;
     }
 
     return 0;
@@ -432,7 +425,7 @@ duk_ret_t duk_make_box2d(duk_context *duk) {
 
   phys2d_applybox(box);
 
-  duk_push_pointer(duk, box);
+  duk_push_pointer(duk, &box->shape);
 
   return 1;
 }
@@ -458,7 +451,9 @@ duk_ret_t duk_make_circle2d(duk_context *duk) {
 
     phys2d_applycircle(circle);
 
-  return 0;
+    duk_push_pointer(duk, &circle->shape);
+
+  return 1;
 }
 
 duk_ret_t duk_anim(duk_context *duk) {
@@ -517,7 +512,6 @@ void ffi_load()
     DUK_FUNC(make_sprite, 3);
     DUK_FUNC(make_anim2d, 4);
     DUK_FUNC(make_box2d, 3);
-    DUK_FUNC(box2d_cmd, DUK_VARARGS);
     DUK_FUNC(make_circle2d, 3);
     DUK_FUNC(cmd, DUK_VARARGS);
     DUK_FUNC(register, 3);
diff --git a/source/engine/sound/mix.c b/source/engine/sound/mix.c
index 31cd821..afa8bb1 100644
--- a/source/engine/sound/mix.c
+++ b/source/engine/sound/mix.c
@@ -14,6 +14,14 @@ short mastermix[BUF_FRAMES*CHANNELS];
 
 static int initted = 0;
 
+static float master_volume = 1.f;
+
+void mix_master_vol(float v) {
+    if (v < 0.f) v = 0.f;
+    if (v > 100.f) v = 100.f;
+    master_volume = v / 100.f;
+}
+
 void mixer_init() {
     for (int i = 0; i < 256; i++) {
         bus[i].next = i+1;
@@ -68,7 +76,7 @@ void bus_fill_buffers(short *master, int n) {
         int nextbus = bus[curbus].next; /* Save this in case busses get changed during fill */
         dsp_run(bus[curbus].in, bus[curbus].buf, BUF_FRAMES);
         for (int i = 0; i < BUF_FRAMES*CHANNELS; i++)
-            master[i] += bus[curbus].buf[i];
+            master[i] += bus[curbus].buf[i] * master_volume;
 
         curbus = nextbus;
     }
diff --git a/source/engine/sound/mix.h b/source/engine/sound/mix.h
index e746341..7913a85 100644
--- a/source/engine/sound/mix.h
+++ b/source/engine/sound/mix.h
@@ -23,7 +23,8 @@ void mixer_init();
 struct bus *first_free_bus(struct dsp_filter in);
 void bus_fill_buffers(short *master, int n);
 
-
+/* Set volume between 0 and 100% */
+void mix_master_vol(float v);
 void bus_free(struct bus *bus);