diff --git a/creatur.cabal b/creatur.cabal
--- a/creatur.cabal
+++ b/creatur.cabal
@@ -1,5 +1,5 @@
 Name:              creatur
-Version:           5.2.1
+Version:           5.2.3
 Stability:         experimental
 Synopsis:          Framework for artificial life experiments.
 Description:       A software framework for automating experiments
@@ -23,6 +23,7 @@
 License-file:      LICENSE
 Copyright:         (c) Amy de Buitléir 2010-2012
 Homepage:          https://github.com/mhwombat/creatur
+Bug-reports:       https://github.com/mhwombat/creatur/issues
 Author:            Amy de Buitléir
 Maintainer:        amy@nualeargais.ie
 Build-Type:        Simple
@@ -35,7 +36,7 @@
 source-repository this
   type:     git
   location: https://github.com/mhwombat/creatur.git
-  tag:      5.2.1
+  tag:      5.2.3
 
 library
   GHC-Options:      -Wall -fno-warn-orphans
@@ -66,13 +67,13 @@
                     base ==4.*,
                     bytestring ==0.10.*,
                     cond ==0.4.*,
-                    cereal ==0.3.* || ==0.4.*,
-                    directory ==1.2.*,
+                    cereal ==0.4.*,
+                    directory ==1.1 || ==1.2.*,
                     filepath ==1.3.*,
                     gray-extended ==1.*,
                     hdaemonize ==0.4.*,
-                    hmatrix ==0.14.* || ==0.15.*,
-                    lens ==3.8.* || ==3.10.*,
+                    hmatrix ==0.14 || ==0.15.*,
+                    lens ==4.0.*,
                     MonadRandom ==0.1.*,
                     mtl ==2.1.*,
                     old-locale ==1.0.*,
@@ -86,22 +87,22 @@
 
 Test-suite creatur-tests
   Type:             exitcode-stdio-1.0
-  Main-is:          Main.hs
+  Main-is:          TestAll.hs
   GHC-Options:      -Wall
   Hs-source-dirs:   test
   Build-Depends:    
                     array ==0.4.* || ==0.5.*,
                     base ==4.*,
-                    binary ==0.5.* || ==0.7.*,
-                    cereal ==0.3.* || ==0.4.*,
+                    binary ==0.5.* || ==0.6.* || ==0.7.*,
+                    cereal ==0.4.*,
                     creatur,
-                    directory ==1.2.*,
+                    directory ==1.1 || ==1.2.*,
                     filepath ==1.3.*,
-                    hmatrix ==0.14.* || ==0.15.*,
+                    hmatrix ==0.14 || ==0.15.*,
                     HUnit ==1.2.*,
                     MonadRandom ==0.1.*,
                     mtl ==2.1.*,
-                    temporary ==1.1.*,
+                    temporary ==1.2.*,
                     test-framework ==0.8.*,
                     test-framework-hunit ==0.3.*,
                     test-framework-quickcheck2 ==0.3.*,
@@ -115,3 +116,16 @@
                     ALife.Creatur.Genetics.BRGCWord8QC
                     ALife.Creatur.Genetics.BRGCWord16QC
                     ALife.Creatur.Genetics.RecombinationQC
+
+-- Benchmark creatur-bench
+--   Type:             exitcode-stdio-1.0
+--   Main-is:          BenchAll.hs
+--   GHC-Options:      -Wall
+--   Hs-source-dirs:   test
+--   Build-Depends:    
+--                     base ==4.*,
+--                     creatur,
+--                     criterion ==0.8.*,
+--                     test-framework ==0.8.*
+--   Other-modules:    ALife.Creatur.Genetics.BRGCWord8Bench
+
diff --git a/src/ALife/Creatur/Genetics/BRGCWord8.hs b/src/ALife/Creatur/Genetics/BRGCWord8.hs
--- a/src/ALife/Creatur/Genetics/BRGCWord8.hs
+++ b/src/ALife/Creatur/Genetics/BRGCWord8.hs
@@ -55,6 +55,7 @@
 import Control.Monad.State.Lazy (StateT, runState, execState, evalState)
 import qualified Control.Monad.State.Lazy as S (put, get, gets)
 import Data.Char (ord, chr)
+import Data.Either (partitionEithers)
 import Data.Functor.Identity (Identity)
 import Data.Word (Word8, Word16)
 import GHC.Generics
@@ -64,10 +65,10 @@
 type Writer = StateT Sequence Identity
 
 write :: Genetic x => x -> Sequence
-write x = execState (put x) []
+write x = runWriter (put x)
 
 runWriter :: Writer () -> Sequence
-runWriter w = execState w []
+runWriter w = execState (w >> finalise) []
 
 type Reader = StateT (Sequence, Int) Identity
 
@@ -185,7 +186,17 @@
     let low = fmap fromIntegral l :: Either [String] Word16
     return . fmap grayToIntegral $ (+) <$> high <*> low
 
-instance (Genetic a) => Genetic [a]
+instance (Genetic a) => Genetic [a] where
+  put xs = put n' >> mapM_ put xs
+    where n = length xs
+          n' = if n <= fromIntegral (maxBound :: Word16)
+                 then fromIntegral n
+                 else error "List too long" :: Word16
+  get = do
+    n <- get :: Reader (Either [String] Word16)
+    case n of
+      Right n' -> getList (fromIntegral n')
+      Left s   -> return $ Left s
 
 instance (Genetic a) => Genetic (Maybe a)
 
@@ -198,11 +209,24 @@
 -- Utilities
 --
 
+finalise :: Writer ()
+finalise = do
+  xs <- S.get
+  S.put (reverse xs)
+
+getList :: Genetic a => Int -> Reader (Either [String] [a])
+getList n = do
+  cs <- sequence $ replicate n get
+  let (mss, xs) = partitionEithers cs
+  if null mss
+    then return $ Right xs
+    else return $ Left (head mss)
+ 
 -- | Write a Word8 value to the genome without encoding it
 putRawWord8 :: Word8 -> Writer ()
 putRawWord8 x = do
   xs <- S.get
-  S.put (xs ++ [x])
+  S.put (x:xs)
 
 -- | Read a Word8 value from the genome without decoding it
 getRawWord8 :: Reader (Either [String] Word8)
@@ -220,7 +244,7 @@
 putRawWord8s :: [Word8] -> Writer ()
 putRawWord8s ys = do
   xs <- S.get
-  S.put (xs ++ ys)
+  S.put (reverse ys ++ xs)
 
 -- | Read a raw sequence of Word8 values from the genome
 getRawWord8s :: Int -> Reader (Either [String] [Word8])
diff --git a/src/ALife/Creatur/Task.hs b/src/ALife/Creatur/Task.hs
--- a/src/ALife/Creatur/Task.hs
+++ b/src/ALife/Creatur/Task.hs
@@ -70,7 +70,7 @@
   atEndOfRound summaryProgram
   (a:_) <- lineup
   markDone a
-    -- do this first in case the next line triggers an exception
+    -- ^^^ do first in case the next line triggers an exception
   withAgent agentProgram a
 
 --   The input parameter is a list of agents. The first agent in the
@@ -89,7 +89,7 @@
   atEndOfRound summaryProgram
   as <- lineup
   when (not $ null as) $ markDone (head as)
-    -- do this first in case the next line triggers an exception
+    -- ^^^ do first in case the next line triggers an exception
   withAgents agentsProgram as
 
 atEndOfRound
diff --git a/test/ALife/Creatur/Genetics/BRGCWord8QC.hs b/test/ALife/Creatur/Genetics/BRGCWord8QC.hs
--- a/test/ALife/Creatur/Genetics/BRGCWord8QC.hs
+++ b/test/ALife/Creatur/Genetics/BRGCWord8QC.hs
@@ -19,6 +19,7 @@
 import Prelude hiding (read)
 import ALife.Creatur.Genetics.BRGCWord8
 import ALife.Creatur.Genetics.Analysis (Analysable)
+import ALife.Creatur.Util (fromEither)
 import Control.Applicative ((<$>), (<*>))
 import Data.Word (Word8, Word16)
 import GHC.Generics (Generic)
@@ -32,6 +33,13 @@
   where x = write g
         g' = read x
 
+prop_rawWord8s_round_trippable :: [Word8] -> Property
+prop_rawWord8s_round_trippable g = property $ g' == g
+  where x = runWriter (putRawWord8s g)
+        g' = fromEither (error "read returned Nothing") .
+               runReader (getRawWord8s n) $ x
+        n = length g
+
 data TestStructure = A | B Bool | C Word8 | D Word16 Char | E [TestStructure]
   deriving (Show, Eq, Generic)
 
@@ -67,7 +75,9 @@
     testProperty "prop_round_trippable - Word16"
       (prop_round_trippable :: Word16 -> Property),
     testProperty "prop_round_trippable - TestStructure"
-      (prop_round_trippable :: TestStructure -> Property)
+      (prop_round_trippable :: TestStructure -> Property),
+    testProperty "prop_rawWord8s_round_trippable"
+      prop_rawWord8s_round_trippable
   ]
 
 
diff --git a/test/Main.hs b/test/Main.hs
deleted file mode 100644
--- a/test/Main.hs
+++ /dev/null
@@ -1,46 +0,0 @@
-------------------------------------------------------------------------
--- |
--- Module      :  Main
--- Copyright   :  (c) Amy de Buitléir 2012-2013
--- License     :  BSD-style
--- Maintainer  :  amy@nualeargais.ie
--- Stability   :  experimental
--- Portability :  portable
---
--- Runs the QuickCheck tests.
---
-------------------------------------------------------------------------
-module Main where
-
-import ALife.Creatur.CounterQC (test)
-import ALife.Creatur.ChecklistQC (test)
-import ALife.Creatur.UniverseQC (test)
-import ALife.Creatur.Database.FileSystemQC (test)
-import ALife.Creatur.UtilQC (test)
-import ALife.Creatur.Genetics.CodeQC (test)
-import ALife.Creatur.Genetics.DiploidQC (test)
-import ALife.Creatur.Genetics.RecombinationQC (test)
-import ALife.Creatur.Genetics.BRGCBoolQC (test)
-import ALife.Creatur.Genetics.BRGCWord8QC (test)
-import ALife.Creatur.Genetics.BRGCWord16QC (test)
-
-import Test.Framework as TF (defaultMain, Test)
-
-tests :: [TF.Test]
-tests = 
-  [ 
-    ALife.Creatur.CounterQC.test,
-    ALife.Creatur.ChecklistQC.test,
-    ALife.Creatur.UniverseQC.test,
-    ALife.Creatur.Database.FileSystemQC.test,
-    ALife.Creatur.UtilQC.test,
-    ALife.Creatur.Genetics.CodeQC.test,
-    ALife.Creatur.Genetics.DiploidQC.test,
-    ALife.Creatur.Genetics.RecombinationQC.test,
-    ALife.Creatur.Genetics.BRGCBoolQC.test,
-    ALife.Creatur.Genetics.BRGCWord8QC.test,
-    ALife.Creatur.Genetics.BRGCWord16QC.test
-  ]
-
-main :: IO ()
-main = defaultMain tests
diff --git a/test/TestAll.hs b/test/TestAll.hs
new file mode 100644
--- /dev/null
+++ b/test/TestAll.hs
@@ -0,0 +1,46 @@
+------------------------------------------------------------------------
+-- |
+-- Module      :  Main
+-- Copyright   :  (c) Amy de Buitléir 2012-2013
+-- License     :  BSD-style
+-- Maintainer  :  amy@nualeargais.ie
+-- Stability   :  experimental
+-- Portability :  portable
+--
+-- Runs the QuickCheck tests.
+--
+------------------------------------------------------------------------
+module Main where
+
+import ALife.Creatur.CounterQC (test)
+import ALife.Creatur.ChecklistQC (test)
+import ALife.Creatur.UniverseQC (test)
+import ALife.Creatur.Database.FileSystemQC (test)
+import ALife.Creatur.UtilQC (test)
+import ALife.Creatur.Genetics.CodeQC (test)
+import ALife.Creatur.Genetics.DiploidQC (test)
+import ALife.Creatur.Genetics.RecombinationQC (test)
+import ALife.Creatur.Genetics.BRGCBoolQC (test)
+import ALife.Creatur.Genetics.BRGCWord8QC (test)
+import ALife.Creatur.Genetics.BRGCWord16QC (test)
+
+import Test.Framework as TF (defaultMain, Test)
+
+tests :: [TF.Test]
+tests = 
+  [ 
+    ALife.Creatur.CounterQC.test,
+    ALife.Creatur.ChecklistQC.test,
+    ALife.Creatur.UniverseQC.test,
+    ALife.Creatur.Database.FileSystemQC.test,
+    ALife.Creatur.UtilQC.test,
+    ALife.Creatur.Genetics.CodeQC.test,
+    ALife.Creatur.Genetics.DiploidQC.test,
+    ALife.Creatur.Genetics.RecombinationQC.test,
+    ALife.Creatur.Genetics.BRGCBoolQC.test,
+    ALife.Creatur.Genetics.BRGCWord8QC.test,
+    ALife.Creatur.Genetics.BRGCWord16QC.test
+  ]
+
+main :: IO ()
+main = defaultMain tests