diff --git a/README.md b/README.md
index e315467..30f7056 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,3 @@
-
 # Spritesheet
 
 Tiny library for working with textures and animated textures.
@@ -8,4 +7,3 @@ Tiny library for working with textures and animated textures.
 - When drawing an image or animation when a shader is defined the library may
   send certain useful constants along, notably `spritesheet_inverse_width` and
 `spritesheet_inverse_height`.
-
diff --git a/spritesheet.lua b/spritesheet.lua
index 2d35e1a..9ef9dba 100644
--- a/spritesheet.lua
+++ b/spritesheet.lua
@@ -1,9 +1,11 @@
+--- Library for managing spritesheets.
+---
+--- Has support for both individual images in spritesheets and animations. This
+--- can be specified from a lua file placed beside the spritesheet image file.
 
-local error_orig = error
 local error, error_internal do
-    error, error_internal  =  error_orig, error_orig
-    error_orig = nil
-    local success, errorlib = pcall(require,'errors')
+    error, error_internal  =  error, error
+    local success, errorlib = pcall(require, 'errors')
     if success then
         error = errorlib 'spritesheet'
         error_internal  =  error.internal
@@ -24,7 +26,7 @@ end
 -- Util
 
 local function calculate_animation_duration (self, frame_i)
-    local frame_i = frame_i or math.huge
+    frame_i = frame_i or math.huge
     assert(type(self) == 'table')
     assert(type(frame_i) == 'number')
 
@@ -119,16 +121,16 @@ local Animation = {}
       Animation.__index = Animation
 
 function Animation.new (self)
-    assert(type(self) == 'table')
+    assert(type(self) == 'table' and self ~= Animation)
     assert(type(self.time) == 'table' or type(self.time) == 'number' and self.time > 0 or type(self.time_total) == 'number')
     assert(#self > 0)
     assert(type(self.time) == 'number' or type(self.time_total) == 'number' or #self == #self.time)
     if self.time_total then  assert(self.time == nil)  end
     assert(self.wrap == nil or self.wrap == true or self.wrap == false)
 
-    local  self = setmetatable(self, Animation)
-           self.duration      =  calculate_animation_duration(self)
-           self.is_animation  =  true
+    setmetatable(self, Animation)
+    self.duration      =  calculate_animation_duration(self)
+    self.is_animation  =  true
 
     -- Contact frame?
     if self.contact_frame then
@@ -282,9 +284,9 @@ local function load_quad_data (filename)
 
         local chunk, error_msg
         if define_love then
-            chunk, error_msg  =  love.filesystem.load(filename..'.lua')
+            chunk, error_msg  =  love.filesystem.load(filename..filetype)
         else
-            chunk, error_msg  =  loadfile(filename..'.lua')
+            chunk, error_msg  =  loadfile(filename..filetype)
         end
 
         if chunk then
diff --git a/test/init.lua b/test/init.lua
index 2126a4a..ef4b605 100644
--- a/test/init.lua
+++ b/test/init.lua
@@ -1 +1 @@
--- TODO
+require 'spritesheet'