diff --git a/constants.js b/constants.js
index 2854de4..c0bbb6a 100644
--- a/constants.js
+++ b/constants.js
@@ -1225,3 +1225,10 @@ const powerups = {
     }
   }
 }
+
+deepFreeze(prodUpgradeText);
+deepFreeze(prodAllUpgradeText);
+deepFreeze(clickUpgradeText);
+deepFreeze(helperUpgradeText);
+deepFreeze(clickVictimUpgradeText);
+deepFreeze(powerupFreqUpgradeText);