diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,3 +10,8 @@
 
 ## 0.2.0.0
 Help messages improved. Module structure refactored. Documentation begun.
+
+## 0.2.0.1
+Revised cabal version in attempt to fix build error on Hackage. Build works
+locally, suspect the problem is a quirk of Hackage build system.
+Added some more documentation.
diff --git a/riichi-scoring.cabal b/riichi-scoring.cabal
--- a/riichi-scoring.cabal
+++ b/riichi-scoring.cabal
@@ -1,4 +1,4 @@
-cabal-version: 3.0
+cabal-version: 2.2
 -- The cabal-version field refers to the version of the .cabal specification,
 -- and can be different from the cabal-install (the tool) version and the
 -- Cabal (the library) version you are using. As such, the Cabal (the library)
@@ -20,7 +20,7 @@
 -- PVP summary:     +-+------- breaking API changes
 --                  | | +----- non-breaking API additions
 --                  | | | +--- code changes with no API change
-version: 0.2.0.0
+version: 0.2.0.1
 -- A short (one-line) description of the package.
 synopsis: A CLI tool for interpreting and scoring Riichi Mahjong hands.
 -- A longer description of the package.
@@ -67,8 +67,8 @@
   hs-source-dirs: src
   build-depends:
     base >=4.19.2.0 && <5,
-    containers >=0.7 && <0.8,
-    mtl >=2.3.1 && <2.4,
+    containers >=0.6.8 && <0.8,
+    mtl >=2.2.2 && <2.4,
 
   default-language: GHC2021
 
@@ -84,8 +84,8 @@
   -- Other library packages from which modules are imported.
   build-depends:
     base >=4.19.2.0 && <5,
-    containers >=0.7 && <0.8,
-    mtl >=2.3.1 && <2.4,
+    containers >=0.6.8 && <0.8,
+    mtl >=2.2.2 && <2.4,
     riichi-lib,
 
   -- Directories containing source files.
@@ -100,7 +100,7 @@
   build-depends:
     base >=4.19.2.0 && <5,
     riichi-lib,
-    tasty,
-    tasty-hunit,
+    tasty >=1.5.4 && <1.6,
+    tasty-hunit >=0.10.2 && <0.11,
 
   default-language: GHC2021
diff --git a/src/Riichi/Display.hs b/src/Riichi/Display.hs
--- a/src/Riichi/Display.hs
+++ b/src/Riichi/Display.hs
@@ -16,6 +16,7 @@
 import Riichi.Waits
 import Riichi.Yaku
 
+-- | Implements the "yaku" command for the CLI. In need of a refactor.
 displayHandYaku :: Hand -> IO ()
 displayHandYaku hand = do
     if length hand < 14
@@ -54,11 +55,13 @@
                         then putStrLn $ toRed "This hand is not valid"
                         else return ()
 
+-- | Implements the "waits" command for the CLI.
 displayHandWaits :: Hand -> IO ()
 displayHandWaits hand = do
     let waits = getWaits hand
     putStrLn $ "Waits are: " ++ (waits & map show & intersperse ", " & concat)
 
+-- | Implements the "score" command for the CLI. In need of a refactor, logic is rather serpentine at the moment.
 displayHandScore :: Hand -> IO ()
 displayHandScore hand = do
     putStrLn "Input dora: (or leave blank)"
diff --git a/src/Riichi/Tile.hs b/src/Riichi/Tile.hs
--- a/src/Riichi/Tile.hs
+++ b/src/Riichi/Tile.hs
@@ -15,17 +15,28 @@
 -}
 data Tile = Honour Honour Dora | Numeric Suit Value Dora deriving (Ord)
 
+-- | Simple type alias. Tracks dora value for a tile. Note red five is represented as dora 1.
 type Dora = Integer
+
+-- | Type alias for the value of a Numeric tile.
 type Value = Integer
 
 -- | An honour tile is a dragon or a wind
 data Honour = Dragon (Dragon) | Wind (Wind) deriving (Show, Eq, Ord)
 
+-- | Dragon enum
 data Dragon = White | Green | Red deriving (Show, Eq, Ord)
+
+-- | Wind enum
 data Wind = North | East | South | West deriving (Show, Eq, Ord)
 
+-- | Suit enum
 data Suit = Man | Pin | Sou deriving (Show, Eq, Ord)
 
+{- | Read a single tile using (semi)standard notation.
+| Winds are upper case, dragons lower case, to remove ambiguity.
+| Red five is denoted by 0.
+-}
 instance Read Tile where
     readsPrec :: Int -> ReadS Tile
     readsPrec _ (x : []) = [(tile, [])]
@@ -58,6 +69,7 @@
                 )
          in [(Numeric suit value dora, [])]
 
+-- | ALlows strings like "123p" and "rrNE" to be read
 readTileBlock :: String -> [Tile]
 readTileBlock string =
     let
@@ -70,6 +82,7 @@
      in
         stripped & map (\c -> [c]) & intersperse separator & concat & (++ separator) & words & map read
 
+-- | Implements an inverse to read
 instance Show Tile where
     show (Honour (Dragon Red) _) = "r"
     show (Honour (Dragon Green) _) = "g"
@@ -85,7 +98,9 @@
     show (Numeric Man n _) = (show n) ++ "m"
     show (Numeric Sou n _) = (show n) ++ "s"
 
--- We don't care about dora when equating tiles
+{- | Almost identical to what would result from deriving Eq on Tile, except we choose to
+| ignore the Dora value
+-}
 instance Eq Tile where
     (==) (Honour honour _) (Honour honour' _) = (honour == honour')
     (==) (Numeric suit value _) (Numeric suit' value' _) = (suit == suit') && (value == value')