diff --git a/src/game/game_info.hpp b/src/game/game_info.hpp
--- a/src/game/game_info.hpp
+++ b/src/game/game_info.hpp
@@ -40,7 +40,7 @@ public:
 	 */
 	const char *GetAPIVersion() const { return this->api_version; }
 
-	/* virtual */ bool IsDeveloperOnly() const { return this->is_developer_only; }
+	bool IsDeveloperOnly() const override { return this->is_developer_only; }
 
 private:
 	int min_loadable_version; ///< The Game can load savegame data if the version is equal or greater than this.