diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,16 @@
 Changelog
 =========
 
+Version 0.2.2.0
+---------------
+
+*July 9, 2020*
+
+<https://github.com/mstksg/mutable/releases/tag/v0.2.2.0>
+
+*   Bugfix: *Generics* mechanisms for `MutBranch` for data types with more than
+    two constructors fixed.
+
 Version 0.2.1.0
 ---------------
 
diff --git a/mutable.cabal b/mutable.cabal
--- a/mutable.cabal
+++ b/mutable.cabal
@@ -4,10 +4,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: ffd197df55f7f93dd8ec419431fdd2c85526097855d397d55d17828e1eebbe95
+-- hash: 9f019adb3428127c9388e91df1ba074ed6013a8bead0bf66c1ed5e2b477a5606
 
 name:           mutable
-version:        0.2.1.0
+version:        0.2.2.0
 synopsis:       Automatic piecewise-mutable references for your types
 description:    Associate and generate "piecewise-mutable" versions for your composite data
                 types.  Think of it like a "generalized MVector for all ADTs".
@@ -44,21 +44,18 @@
       Data.Mutable.Branches
       Data.Mutable.Class
       Data.Mutable.Instances
-      Data.Mutable.Internal.TH
       Data.Mutable.Parts
   other-modules:
       Data.Mutable.Internal
+      Data.Mutable.Internal.TH
   hs-source-dirs:
       src
   ghc-options: -Wall -Wcompat -Wredundant-constraints -Werror=incomplete-patterns
   build-depends:
-      base >=4.11 && <5
-    , constraints
+      base >=4.12 && <5
     , generic-lens >=2.0
     , generic-lens-core >=2.0
-    , microlens
     , primitive >=0.6.4
-    , reflection
     , template-haskell
     , transformers
     , vector
diff --git a/src/Data/Mutable/Branches.hs b/src/Data/Mutable/Branches.hs
--- a/src/Data/Mutable/Branches.hs
+++ b/src/Data/Mutable/Branches.hs
@@ -592,6 +592,7 @@
     gmbcProj  = gmbsProj @ctor @(GL.HasCtorP ctor l)
     gmbcEmbed = gmbsEmbed @ctor @(GL.HasCtorP ctor l)
 
+
 class ( GMutable s l
       , GMutable s r
       , Mutable s a
@@ -626,18 +627,16 @@
 instance
       ( GMutable s l
       , GMutBranchConstructor ctor s r a
-      , GIsList (GRef_ s r) (GRef_ s r) (MapRef s as) (MapRef s as)
-      , GIsList r r as as
-      , ListTuple a a as as
-      , ListRefTuple s b as
       , Ref s a ~ b
       )
       => GMutBranchSum ctor 'False s l r a where
     gmbsProj lb (MutSumF r) = readMutVar r >>= \case
       L1 _ -> pure Nothing
       R1 x -> gmbcProj lb x
-    gmbsEmbed _ = fmap MutSumF . newMutVar . R1
-                . GLP.view (GL.fromIso (glist . tupledRef @s @b @as))
+    gmbsEmbed lb r = do
+      gr <- gmbcEmbed lb r
+      MutSumF <$> newMutVar (R1 gr)
+
 
 -- | Create a 'MutBranch' for any data type with a 'Generic' instance by
 -- specifying the constructor name using OverloadedLabels