diff --git a/spine-c/include/spine/Atlas.h b/spine-c/include/spine/Atlas.h
index 14e8175fd..18c9f884e 100644
--- a/spine-c/include/spine/Atlas.h
+++ b/spine-c/include/spine/Atlas.h
@@ -32,17 +32,17 @@ extern "C" {
 #endif
 
 typedef enum {
-	ATLAS_ALPHA, ATLAS_INTENSITY, ATLAS_LUMINANCEALPHA, ATLAS_RGB565, ATLAS_RGBA4444, ATLAS_RGB888, ATLAS_RGBA8888
+	ATLAS_ALPHA, ATLAS_INTENSITY, ATLAS_LUMINANCE_ALPHA, ATLAS_RGB565, ATLAS_RGBA4444, ATLAS_RGB888, ATLAS_RGBA8888
 } AtlasFormat;
 
 typedef enum {
 	ATLAS_NEAREST,
 	ATLAS_LINEAR,
 	ATLAS_MIPMAP,
-	ATLAS_MIPMAPNEARESTNEAREST,
-	ATLAS_MIPMAPLINEARNEAREST,
-	ATLAS_MIPMAPNEARESTLINEAR,
-	ATLAS_MIPMAPLINEARLINEAR
+	ATLAS_MIPMAP_NEAREST_NEAREST,
+	ATLAS_MIPMAP_LINEAR_NEAREST,
+	ATLAS_MIPMAP_NEAREST_LINEAR,
+	ATLAS_MIPMAP_LINEAR_LINEAR
 } AtlasFilter;
 
 typedef enum {
@@ -94,6 +94,7 @@ Atlas* Atlas_readAtlas (const char* data);
 Atlas* Atlas_readAtlasFile (const char* path);
 void Atlas_free (Atlas* atlas);
 
+/* Returns 0 if the region was not found. */
 AtlasRegion* Atlas_findRegion (const Atlas* atlas, const char* name);
 
 #ifdef __cplusplus
diff --git a/spine-c/include/spine/Attachment.h b/spine-c/include/spine/Attachment.h
index 041280d16..4e7180f76 100644
--- a/spine-c/include/spine/Attachment.h
+++ b/spine-c/include/spine/Attachment.h
@@ -40,7 +40,7 @@ typedef enum {
 typedef struct Attachment Attachment;
 struct Attachment {
 	const char* const name;
-	int type;
+	AttachmentType type;
 
 	const void* const vtable;
 };
diff --git a/spine-c/include/spine/AttachmentLoader.h b/spine-c/include/spine/AttachmentLoader.h
index ab49b44c8..500d6d930 100644
--- a/spine-c/include/spine/AttachmentLoader.h
+++ b/spine-c/include/spine/AttachmentLoader.h
@@ -43,6 +43,7 @@ struct AttachmentLoader {
 
 void AttachmentLoader_free (AttachmentLoader* loader);
 
+/* Returns 0 to not load an attachment. If 0 is returned and AttachmentLoader.error1 is set, an error occurred. */
 Attachment* AttachmentLoader_newAttachment (AttachmentLoader* loader, AttachmentType type, const char* name);
 
 #ifdef __cplusplus
diff --git a/spine-c/include/spine/Bone.h b/spine-c/include/spine/Bone.h
index fff25013e..e3ce345a8 100644
--- a/spine-c/include/spine/Bone.h
+++ b/spine-c/include/spine/Bone.h
@@ -49,7 +49,7 @@ struct Bone {
 
 void Bone_setYDown (int/*bool*/yDown);
 
-/* @param parent May be zero. */
+/* @param parent May be 0. */
 Bone* Bone_new (BoneData* data, Bone* parent);
 void Bone_free (Bone* bone);
 
diff --git a/spine-c/include/spine/RegionAttachment.h b/spine-c/include/spine/RegionAttachment.h
index 438ecda1e..3ceb798a0 100644
--- a/spine-c/include/spine/RegionAttachment.h
+++ b/spine-c/include/spine/RegionAttachment.h
@@ -41,10 +41,10 @@ struct RegionAttachment {
 	float offset[8];
 };
 
-void RegionAttachment_updateOffset (RegionAttachment* attachment);
-
 RegionAttachment* RegionAttachment_new (const char* name, AtlasRegion* region);
 
+void RegionAttachment_updateOffset (RegionAttachment* attachment);
+
 #ifdef __cplusplus
 }
 }
diff --git a/spine-c/include/spine/Skeleton.h b/spine-c/include/spine/Skeleton.h
index 4206a224b..d819dd5b3 100644
--- a/spine-c/include/spine/Skeleton.h
+++ b/spine-c/include/spine/Skeleton.h
@@ -64,26 +64,26 @@ void Skeleton_setBonesToBindPose (const Skeleton* skeleton);
 void Skeleton_setSlotsToBindPose (const Skeleton* skeleton);
 
 Bone* Skeleton_getRootBone (const Skeleton* skeleton);
-/* Returns 0 if the bone could not be found. */
+/* Returns 0 if the bone was not found. */
 Bone* Skeleton_findBone (const Skeleton* skeleton, const char* boneName);
-/* Returns -1 if the bone could not be found. */
+/* Returns -1 if the bone was not found. */
 int Skeleton_findBoneIndex (const Skeleton* skeleton, const char* boneName);
 
-/* Returns 0 if the slot could not be found. */
+/* Returns 0 if the slot was not found. */
 Slot* Skeleton_findSlot (const Skeleton* skeleton, const char* slotName);
-/* Returns -1 if the slot could not be found. */
+/* Returns -1 if the slot was not found. */
 int Skeleton_findSlotIndex (const Skeleton* skeleton, const char* slotName);
 
-/* Returns 0 if the skin could not be found. */
+/* Returns 0 if the skin was not found. */
 int Skeleton_setSkinByName (Skeleton* skeleton, const char* skinName);
 /* @param skin May be 0.*/
 void Skeleton_setSkin (Skeleton* skeleton, Skin* skin);
 
-/* Returns 0 if the slot or attachment could not be found. */
+/* Returns 0 if the slot or attachment was not found. */
 Attachment* Skeleton_getAttachmentForSlotName (const Skeleton* skeleton, const char* slotName, const char* attachmentName);
-/* Returns 0 if the slot or attachment could not be found. */
+/* Returns 0 if the slot or attachment was not found. */
 Attachment* Skeleton_getAttachmentForSlotIndex (const Skeleton* skeleton, int slotIndex, const char* attachmentName);
-/* Returns 0 if the slot or attachment could not be found. */
+/* Returns 0 if the slot or attachment was not found. */
 int Skeleton_setAttachment (Skeleton* skeleton, const char* slotName, const char* attachmentName);
 
 void Skeleton_update (Skeleton* skeleton, float deltaTime);
diff --git a/spine-c/include/spine/Skin.h b/spine-c/include/spine/Skin.h
index 5327a8a83..b7eb7b762 100644
--- a/spine-c/include/spine/Skin.h
+++ b/spine-c/include/spine/Skin.h
@@ -51,7 +51,7 @@ void Skin_free (Skin* skin);
 
 /* The Skin owns the attachment. */
 void Skin_addAttachment (Skin* skin, int slotIndex, const char* name, Attachment* attachment);
-/* May return null. */
+/* Returns 0 if the attachment was not found. */
 Attachment* Skin_getAttachment (const Skin* skin, int slotIndex, const char* name);
 
 #ifdef __cplusplus
diff --git a/spine-c/include/spine/Slot.h b/spine-c/include/spine/Slot.h
index 1c28151ed..3e4098015 100644
--- a/spine-c/include/spine/Slot.h
+++ b/spine-c/include/spine/Slot.h
@@ -48,7 +48,7 @@ typedef struct Slot {
 Slot* Slot_new (SlotData* data, struct Skeleton* skeleton, Bone* bone);
 void Slot_free (Slot* slot);
 
-/* @param attachment May be null. */
+/* @param attachment May be 0 to clear the attachment for the slot. */
 void Slot_setAttachment (Slot* slot, Attachment* attachment);
 
 void Slot_setAttachmentTime (Slot* slot, float time);
diff --git a/spine-c/include/spine/SlotData.h b/spine-c/include/spine/SlotData.h
index 7b4a3d142..608c0c196 100644
--- a/spine-c/include/spine/SlotData.h
+++ b/spine-c/include/spine/SlotData.h
@@ -43,7 +43,7 @@ typedef struct {
 SlotData* SlotData_new (const char* name, BoneData* boneData);
 void SlotData_free (SlotData* slotData);
 
-/* @param attachmentName May be zero. */
+/* @param attachmentName May be 0 for no bind pose attachment. */
 void SlotData_setAttachmentName (SlotData* slotData, const char* attachmentName);
 
 #ifdef __cplusplus
diff --git a/spine-c/include/spine/extension.h b/spine-c/include/spine/extension.h
index b9c92cacb..75e149e5e 100644
--- a/spine-c/include/spine/extension.h
+++ b/spine-c/include/spine/extension.h
@@ -45,7 +45,7 @@
  expose a vtable.
 
  - The public API hides implementation details such as vtable structs and init/deinit functions. An internal API is exposed in
- extension.h to allow classes to be extended.
+ extension.h to allow classes to be extended. Internal structs and functions begin with underscore (_).
 
  - OOP in C tends to lose type safety. Macros are provided in extension.h to give more context about why a cast is being done.
  */
@@ -70,7 +70,7 @@
 /* Casts away const. Can be used as an lvalue. Not type safe, use with care. */
 #define CONST_CAST(TYPE,VALUE) (*(TYPE*)&VALUE)
 
-/* Gets the vtable for the specified type. Can be used as an lvalue. */
+/* Gets the vtable for the specified type. Not type safe, use with care. */
 #define VTABLE(TYPE,VALUE) ((_##TYPE##Vtable*)((TYPE*)VALUE)->vtable)
 
 /* Frees memory. Can be used on const. */
diff --git a/spine-c/src/spine/Atlas.c b/spine-c/src/spine/Atlas.c
index f317301db..5263e02f8 100644
--- a/spine-c/src/spine/Atlas.c
+++ b/spine-c/src/spine/Atlas.c
@@ -39,7 +39,6 @@ void _AtlasPage_deinit (AtlasPage* self) {
 }
 
 void AtlasPage_free (AtlasPage* self) {
-	if (self->next) AtlasPage_free(self->next); /* BOZO - Don't dispose all in the list. */
 	VTABLE(AtlasPage, self) ->free(self);
 }
 
@@ -50,7 +49,6 @@ AtlasRegion* AtlasRegion_new () {
 }
 
 void AtlasRegion_free (AtlasRegion* self) {
-	if (self->next) AtlasRegion_free(self->next);
 	FREE(self->name);
 	FREE(self->splits);
 	FREE(self->pads);
@@ -162,6 +160,11 @@ static int toInt (Str* str) {
 	return strtol(str->begin, (char**)&str->end, 10);
 }
 
+static Atlas* abort (Atlas* self) {
+	Atlas_free(self);
+	return 0;
+}
+
 static const char* formatNames[] = {"Alpha", "Intensity", "LuminanceAlpha", "RGB565", "RGBA4444", "RGB888", "RGBA8888"};
 static const char* textureFilterNames[] = {"Nearest", "Linear", "MipMap", "MipMapNearestNearest", "MipMapLinearNearest",
 		"MipMapNearestLinear", "MipMapLinearLinear"};
@@ -186,14 +189,14 @@ Atlas* Atlas_readAtlas (const char* data) {
 				self->pages = page;
 			lastPage = page;
 
-			if (!readValue(&str)) return 0;
+			if (!readValue(&str)) return abort(self);
 			page->format = (AtlasFormat)indexOf(formatNames, 7, &str);
 
-			if (!readTuple(tuple)) return 0;
+			if (!readTuple(tuple)) return abort(self);
 			page->minFilter = (AtlasFilter)indexOf(textureFilterNames, 7, tuple);
 			page->magFilter = (AtlasFilter)indexOf(textureFilterNames, 7, tuple + 1);
 
-			if (!readValue(&str)) return 0;
+			if (!readValue(&str)) return abort(self);
 			if (!equals(&str, "none")) {
 				page->uWrap = *str.begin == 'x' ? ATLAS_REPEAT : (*str.begin == 'y' ? ATLAS_CLAMPTOEDGE : ATLAS_REPEAT);
 				page->vWrap = *str.begin == 'x' ? ATLAS_CLAMPTOEDGE : (*str.begin == 'y' ? ATLAS_REPEAT : ATLAS_REPEAT);
@@ -209,19 +212,19 @@ Atlas* Atlas_readAtlas (const char* data) {
 			region->page = page;
 			region->name = mallocString(&str);
 
-			if (!readValue(&str)) return 0;
+			if (!readValue(&str)) return abort(self);
 			region->rotate = equals(&str, "true");
 
-			if (readTuple(tuple) != 2) return 0;
+			if (readTuple(tuple) != 2) return abort(self);
 			region->x = toInt(tuple);
 			region->y = toInt(tuple + 1);
 
-			if (readTuple(tuple) != 2) return 0;
+			if (readTuple(tuple) != 2) return abort(self);
 			region->width = toInt(tuple);
 			region->height = toInt(tuple + 1);
 
 			int count;
-			if (!(count = readTuple(tuple))) return 0;
+			if (!(count = readTuple(tuple))) return abort(self);
 			if (count == 4) { /* split is optional */
 				region->splits = MALLOC(int, 4);
 				region->splits[0] = toInt(tuple);
@@ -229,7 +232,7 @@ Atlas* Atlas_readAtlas (const char* data) {
 				region->splits[2] = toInt(tuple + 2);
 				region->splits[3] = toInt(tuple + 3);
 
-				if (!(count = readTuple(tuple))) return 0;
+				if (!(count = readTuple(tuple))) return abort(self);
 				if (count == 4) { /* pad is optional, but only present with splits */
 					region->pads = MALLOC(int, 4);
 					region->pads[0] = toInt(tuple);
@@ -237,7 +240,7 @@ Atlas* Atlas_readAtlas (const char* data) {
 					region->pads[2] = toInt(tuple + 2);
 					region->pads[3] = toInt(tuple + 3);
 
-					if (!readTuple(tuple)) return 0;
+					if (!readTuple(tuple)) return abort(self);
 				}
 			}
 
@@ -248,7 +251,7 @@ Atlas* Atlas_readAtlas (const char* data) {
 			region->offsetX = (float)toInt(tuple);
 			region->offsetY = (float)toInt(tuple + 1);
 
-			if (!readValue(&str)) return 0;
+			if (!readValue(&str)) return abort(self);
 			region->index = toInt(&str);
 		}
 	}
@@ -265,8 +268,20 @@ Atlas* Atlas_readAtlasFile (const char* path) {
 }
 
 void Atlas_free (Atlas* self) {
-	if (self->pages) AtlasPage_free(self->pages);
-	if (self->regions) AtlasRegion_free(self->regions);
+	AtlasPage* page = self->pages;
+	while (page) {
+		AtlasPage* nextPage = page->next;
+		AtlasPage_free(page);
+		page = nextPage;
+	}
+
+	AtlasRegion* region = self->regions;
+	while (region) {
+		AtlasRegion* nextRegion = region->next;
+		AtlasRegion_free(region);
+		region = nextRegion;
+	}
+
 	FREE(self);
 }
 
diff --git a/spine-c/src/spine/SkeletonJson.c b/spine-c/src/spine/SkeletonJson.c
index b96c0fabd..ec2437e9c 100644
--- a/spine-c/src/spine/SkeletonJson.c
+++ b/spine-c/src/spine/SkeletonJson.c
@@ -208,10 +208,13 @@ SkeletonData* SkeletonJson_readSkeletonData (SkeletonJson* self, const char* jso
 					}
 
 					Attachment* attachment = AttachmentLoader_newAttachment(self->attachmentLoader, type, attachmentName);
-					if (!attachment && self->attachmentLoader->error1) {
-						SkeletonData_free(skeletonData);
-						_SkeletonJson_setError(self, root, self->attachmentLoader->error1, self->attachmentLoader->error2);
-						return 0;
+					if (!attachment) {
+						if (self->attachmentLoader->error1) {
+							SkeletonData_free(skeletonData);
+							_SkeletonJson_setError(self, root, self->attachmentLoader->error1, self->attachmentLoader->error2);
+							return 0;
+						}
+						continue;
 					}
 
 					if (attachment->type == ATTACHMENT_REGION || attachment->type == ATTACHMENT_REGION_SEQUENCE) {
diff --git a/spine-c/src/spine/Skin.c b/spine-c/src/spine/Skin.c
index 5bace7530..c8d41485d 100644
--- a/spine-c/src/spine/Skin.c
+++ b/spine-c/src/spine/Skin.c
@@ -36,7 +36,6 @@ SkinEntry* _SkinEntry_new (int slotIndex, const char* name, Attachment* attachme
 }
 
 void _SkinEntry_free (SkinEntry* self) {
-	if (self->next) _SkinEntry_free(CONST_CAST(SkinEntry*, self->next) );
 	Attachment_free(self->attachment);
 	FREE(self->name);
 	FREE(self);
@@ -51,7 +50,13 @@ Skin* Skin_new (const char* name) {
 }
 
 void Skin_free (Skin* self) {
-	_SkinEntry_free(CONST_CAST(SkinEntry*, self->entries) );
+	SkinEntry* entry = CONST_CAST(SkinEntry*, self->entries);
+	while (entry) {
+		SkinEntry* nextEtry = CONST_CAST(SkinEntry*, entry->next);
+		_SkinEntry_free(entry);
+		entry = nextEtry;
+	}
+
 	FREE(self->name);
 	FREE(self);
 }
diff --git a/spine-c/src/spine/Slot.c b/spine-c/src/spine/Slot.c
index c55f88588..2844816e6 100644
--- a/spine-c/src/spine/Slot.c
+++ b/spine-c/src/spine/Slot.c
@@ -48,7 +48,6 @@ void Slot_free (Slot* self) {
 	FREE(self);
 }
 
-/* @param attachment May be null. */
 void Slot_setAttachment (Slot* self, Attachment* attachment) {
 	CONST_CAST(Attachment*, self->attachment) = attachment;
 	SUB_CAST(_Internal, self) ->attachmentTime = self->skeleton->time;