diff --git a/src/common/HighScoresManager.cxx b/src/common/HighScoresManager.cxx
index 8d47cc329..d471808cc 100644
--- a/src/common/HighScoresManager.cxx
+++ b/src/common/HighScoresManager.cxx
@@ -565,7 +565,7 @@ Int32 HighScoresManager::fromBCD(uInt8 bcd) const
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-string HighScoresManager::hash(ScoresData& data) const
+string HighScoresManager::hash(const ScoresData& data) const
 {
   ostringstream buf;
 
diff --git a/src/common/HighScoresManager.hxx b/src/common/HighScoresManager.hxx
index 9528d3385..3dfd0da54 100644
--- a/src/common/HighScoresManager.hxx
+++ b/src/common/HighScoresManager.hxx
@@ -54,31 +54,31 @@ namespace HSM {
 
   struct ScoresProps {
     // Formats
-    uInt32 numDigits;
-    uInt32 trailingZeroes;
-    bool scoreBCD;
-    bool scoreInvert;
-    bool varsBCD;
-    bool varsZeroBased;
+    uInt32 numDigits{0};
+    uInt32 trailingZeroes{0};
+    bool scoreBCD{false};
+    bool scoreInvert{false};
+    bool varsBCD{false};
+    bool varsZeroBased{false};
     string special;
-    bool specialBCD;
-    bool specialZeroBased;
+    bool specialBCD{false};
+    bool specialZeroBased{false};
     string notes;
     // Addresses
     ScoreAddresses scoreAddr;
-    uInt16 varsAddr;
-    uInt16 specialAddr;
+    uInt16 varsAddr{0};
+    uInt16 specialAddr{0};
   };
 
   struct ScoreEntry {
-    Int32 score;
-    Int32 special;
+    Int32 score{0};
+    Int32 special{0};
     string name;
     string date;
   };
 
   struct ScoresData {
-    Int32 variation;
+    Int32 variation{0};
     string md5;
     ScoreEntry scores[NUM_RANKS];
   };
@@ -232,7 +232,7 @@ class HighScoresManager
 
     uInt16 fromHexStr(const string& addr) const;
     Int32 fromBCD(uInt8 bcd) const;
-    string hash(HSM::ScoresData& data) const;
+    string hash(const HSM::ScoresData& data) const;
 
     /**
       Loads the current high scores for this game and variation from the given JSON object.
diff --git a/src/common/repository/CompositeKVRJsonAdapter.cxx b/src/common/repository/CompositeKVRJsonAdapter.cxx
index 0ef8cd8c0..62d1bd9a5 100644
--- a/src/common/repository/CompositeKVRJsonAdapter.cxx
+++ b/src/common/repository/CompositeKVRJsonAdapter.cxx
@@ -24,7 +24,7 @@ namespace {
   class ProxyRepository : public KeyValueRepository {
       public:
         ProxyRepository(KeyValueRepositoryAtomic& kvr, const string& key)
-          : myKvr(kvr), myKey(key)
+          : myKvr{kvr}, myKey{key}
         {}
 
         std::map<string, Variant> load() override {
@@ -55,7 +55,7 @@ namespace {
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 CompositeKVRJsonAdapter::CompositeKVRJsonAdapter(KeyValueRepositoryAtomic& kvr)
-  : myKvr(kvr)
+  : myKvr{kvr}
 {}
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
diff --git a/src/common/repository/CompositeKVRJsonAdapter.hxx b/src/common/repository/CompositeKVRJsonAdapter.hxx
index 950782207..026fa18cd 100644
--- a/src/common/repository/CompositeKVRJsonAdapter.hxx
+++ b/src/common/repository/CompositeKVRJsonAdapter.hxx
@@ -25,7 +25,7 @@
 class CompositeKVRJsonAdapter : public CompositeKeyValueRepository {
   public:
 
-    CompositeKVRJsonAdapter(KeyValueRepositoryAtomic& kvr);
+    explicit CompositeKVRJsonAdapter(KeyValueRepositoryAtomic& kvr);
 
     shared_ptr<KeyValueRepository> get(const string& key) override;
 
diff --git a/src/common/repository/CompositeKeyValueRepositoryNoop.hxx b/src/common/repository/CompositeKeyValueRepositoryNoop.hxx
index a2457ee69..2c658b00f 100644
--- a/src/common/repository/CompositeKeyValueRepositoryNoop.hxx
+++ b/src/common/repository/CompositeKeyValueRepositoryNoop.hxx
@@ -29,11 +29,13 @@ class CompositeKeyValueRepositoryNoop : public CompositeKeyValueRepositoryAtomic
     using CompositeKeyValueRepositoryAtomic::remove;
     using CompositeKeyValueRepositoryAtomic::get;
 
-    shared_ptr<KeyValueRepository> get(const string& key) { return make_shared<KeyValueRepositoryNoop>(); }
+    shared_ptr<KeyValueRepository> get(const string& key) override {
+      return make_shared<KeyValueRepositoryNoop>();
+    }
 
-    bool has(const string& key) { return false; }
+    bool has(const string& key) override { return false; }
 
-    void remove(const string& key) {}
+    void remove(const string& key) override {}
 };
 
 #endif // COMPOSITE_KEY_VALUE_REPOSITORY_NOOP_HXX
diff --git a/src/common/repository/KeyValueRepositoryConfigfile.hxx b/src/common/repository/KeyValueRepositoryConfigfile.hxx
index 3b613d816..595bc8a19 100644
--- a/src/common/repository/KeyValueRepositoryConfigfile.hxx
+++ b/src/common/repository/KeyValueRepositoryConfigfile.hxx
@@ -27,7 +27,7 @@ class KeyValueRepositoryConfigfile : public KeyValueRepositoryFile<KeyValueRepos
     using KeyValueRepositoryFile<KeyValueRepositoryConfigfile>::load;
     using KeyValueRepositoryFile<KeyValueRepositoryConfigfile>::save;
 
-    KeyValueRepositoryConfigfile(const FilesystemNode& node);
+    explicit KeyValueRepositoryConfigfile(const FilesystemNode& node);
 
     static std::map<string, Variant> load(istream& in);
 
diff --git a/src/common/repository/KeyValueRepositoryFile.hxx b/src/common/repository/KeyValueRepositoryFile.hxx
index 23bccb891..333eff03a 100644
--- a/src/common/repository/KeyValueRepositoryFile.hxx
+++ b/src/common/repository/KeyValueRepositoryFile.hxx
@@ -46,7 +46,7 @@ class KeyValueRepositoryFile : public KeyValueRepository {
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 template<class T>
 KeyValueRepositoryFile<T>::KeyValueRepositoryFile(const FilesystemNode& node)
-  : myNode(node)
+  : myNode{node}
 {}
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
diff --git a/src/gui/HighScoresMenu.cxx b/src/gui/HighScoresMenu.cxx
index 93c388436..fade474e4 100644
--- a/src/gui/HighScoresMenu.cxx
+++ b/src/gui/HighScoresMenu.cxx
@@ -22,7 +22,7 @@
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 HighScoresMenu::HighScoresMenu(OSystem& osystem)
-  : DialogContainer(osystem)
+  : DialogContainer{osystem}
 {
 }