diff --git a/constants.js b/constants.js
index 0c0d454..2854de4 100644
--- a/constants.js
+++ b/constants.js
@@ -2,168 +2,249 @@
 
 const resourceTypes = {
   "food": {
-    name: "Food"
+    name: "food"
   }
 }
+
+deepFreeze(resourceTypes);
+
 const buildings = {
   "micro": {
     "name": "Micro",
     "plural": "Micros",
     "desc": "A tasty, squirmy treat.",
-    "cost": 1e1,
-    "prod": 1e-1 / 1,
+    "cost": {
+      "food": 1e1
+    },
+    "prod": {
+      "food": 1e-1 / 1
+    },
     "icon": "fa-universal-access"
   },
   "anthro": {
     "name": "Anthro",
     "plural": "Anthros",
     "desc": "Something more substantial to sate your hunger.",
-    "cost": 1e2,
-    "prod": 1e0 / 1.1,
+    "cost": {
+      "food": 1e2
+    },
+    "prod": {
+      "food": 1e0 / 1.1
+    },
     "icon": "fa-male"
   },
   "car": {
     "name": "Car",
     "plural": "Cars",
     "desc": "Crunchy shell, tasty center.",
-    "cost": 1.2e3,
-    "prod": 1e1 / 1.2,
+    "cost": {
+      "food": 1.2e3
+    },
+    "prod": {
+      "food": 1e1 / 1.2
+    },
     "icon": "fa-car"
   },
   "bus": {
     "name": "Bus",
     "plural": "Buses",
     "desc": "Probably the worst place to be when a macro is aroud.",
-    "cost": 1.4e4,
-    "prod": 1e2 / 1.3,
+    "cost": {
+      "food": 1.4e4
+    },
+    "prod": {
+      "food": 1e2 / 1.3
+    },
     "icon": "fa-bus"
   },
   "house": {
     "name": "House",
     "plural": "Houses",
     "desc": "Home sweet home - but it doesn't taste sweet?",
-    "cost": 1.6e5,
-    "prod": 1e3 / 1.4,
+    "cost": {
+      "food": 1.6e5
+    },
+    "prod": {
+      "food": 1e3 / 1.4
+    },
     "icon": "fa-home"
   },
   "apartment": {
     "name": "Apartment",
     "plural": "Apartments",
     "desc": "More snacks, less packaging.",
-    "cost": 1.8e6,
-    "prod": 1e4 / 1.5,
+    "cost": {
+      "food": 1.8e6
+    },
+    "prod": {
+      "food": 1e4 / 1.5
+    },
     "icon": "fa-building"
   },
   "block": {
     "name": "Block",
     "plural": "Blocks",
     "desc": "A whole pile of buildings.",
-    "cost": 2e7,
-    "prod": 1e5 / 1.6,
+    "cost": {
+      "food": 2e7
+    },
+    "prod": {
+      "food": 1e5 / 1.6
+    },
     "icon": "fa-warehouse"
   },
   "town": {
     "name": "Town",
     "plural": "Towns",
     "desc": "'Tourist trap' has never been this literal.",
-    "cost": 2.2e8,
-    "prod": 1e6 / 1.7,
+    "cost": {
+      "food": 2.2e8
+    },
+    "prod": {
+      "food": 1e6 / 1.7
+    },
     "icon": "fa-store"
   },
   "city": {
     "name": "City",
     "plural": "Cities",
     "desc": "Please no sitty on our city.",
-    "cost": 2.4e9,
-    "prod": 1e7 / 1.8,
+    "cost": {
+      "food": 2.4e9
+    },
+    "prod": {
+      "food": 1e7 / 1.8
+    },
     "icon": "fa-city"
   },
   "metro": {
     "name": "Metropolis",
     "plural": "Metropolises",
     "desc": "A big ol' city. Tasty, too.",
-    "cost": 2.6e10,
-    "prod": 1e8 / 1.9,
+    "cost": {
+      "food": 2.6e10
+    },
+    "prod": {
+      "food": 1e8 / 1.9
+    },
     "icon": "fa-landmark"
   },
   "county": {
     "name": "County",
     "plural": "Counties",
     "desc": "Why salt the land when you can slurp it?",
-    "cost": 2.8e11,
-    "prod": 1e9 / 2,
+    "cost": {
+      "food": 2.8e11
+    },
+    "prod": {
+      "food": 1e9 / 2
+    },
     "icon": "fa-map"
   },
   "state": {
     "name": "State",
     "plural": "States",
     "desc": "The United States is made up of...43 states - no, 42...",
-    "cost": 3e12,
-    "prod": 1e10 / 2.1,
+    "cost": {
+      "food": 3e12
+    },
+    "prod": {
+      "food": 1e10 / 2.1
+    },
     "icon": "fa-map-signs"
   },
   "country": {
     "name": "Country",
     "plural": "Countries",
     "desc": "One nation, under paw.",
-    "cost": 3.2e13,
-    "prod": 1e11 / 2.2,
+    "cost": {
+      "food": 3.2e13
+    },
+    "prod": {
+      "food": 1e11 / 2.2
+    },
     "icon": "fa-flag"
   },
   "continent": {
     "name": "Continent",
     "plural": "Continents",
     "desc": "Earth-shattering appetite!",
-    "cost": 3.4e14,
-    "prod": 1e12 / 2.3,
+    "cost": {
+      "food": 3.4e14
+    },
+    "prod": {
+      "food": 1e12 / 2.3
+    },
     "icon": "fa-mountain"
   },
   "planet": {
     "name": "Planet",
     "plural": "Planets",
     "desc": "Earth appetite!",
-    "cost": 3.6e15,
-    "prod": 1e13 / 2.4,
+    "cost": {
+      "food": 3.6e15
+    },
+    "prod": {
+      "food": 1e13 / 2.4
+    },
     "icon": "fa-globe-europe"
   },
   "solar-system": {
     "name": "Solar System",
     "plural": "Solar Systems",
     "desc": "Earths appetite!",
-    "cost": 3.8e16,
-    "prod": 1e14 / 2.5,
+    "cost": {
+      "food": 3.8e16
+    },
+    "prod": {
+      "food": 1e14 / 2.5
+    },
     "icon": "fa-meteor"
   },
   "galaxy": {
     "name": "Galaxy",
     "plural": "Galaxies",
     "desc": "In a galaxy far, far down your gullet...",
-    "cost": 4.0e17,
-    "prod": 1e15 / 2.6,
+    "cost": {
+      "food": 4.0e17
+    },
+    "prod": {
+      "food": 1e15 / 2.6
+    },
     "icon": "fa-sun"
   },
   "universe": {
     "name": "Universe",
     "plural": "Universes",
     "desc": "Into the you-verse.",
-    "cost": 4.2e18,
-    "prod": 1e16 / 2.7,
+    "cost": {
+      "food": 4.2e18
+    },
+    "prod": {
+      "food": 1e16 / 2.7
+    },
     "icon": "fa-asterisk"
   },
   "multiverse": {
     "name": "Multiverse",
     "plural": "Multiverses",
     "desc": "This is getting very silly.",
-    "cost": 4.4e19,
-    "prod": 1e17 / 2.8,
+    "cost": {
+      "food": 4.4e19
+    },
+    "prod": {
+      "food": 1e17 / 2.8
+    },
     "icon": "fa-infinity"
   }
 }
 
+deepFreeze(buildings);
+
 const effect_types = {
   "prod": {
     "apply": function (effect, productivity) {
-      return productivity * effect.amount;
+      scaleCost(productivity, effect);
     },
     "desc": function (effect) {
       return round(effect.amount, 2) + "x food production from " + buildings[effect.target].plural;
@@ -171,7 +252,7 @@ const effect_types = {
   },
   "prod-all": {
     "apply": function (effect, productivity) {
-      return productivity * effect.amount;
+      scaleCost(productivity, effect);
     },
     "desc": function (effect) {
       return round((effect.amount - 1) * 100) + "% increase to food production";
@@ -208,6 +289,8 @@ const effect_types = {
   }
 }
 
+deepFreeze(effect_types);
+
 let upgrades = {
 
 }
@@ -219,6 +302,7 @@ function createTemplateUpgrades() {
   createHelperUpgrades();
   createClickVictimUpgrades();
   createPowerupFreqUpgrades();
+  deepFreeze(upgrades);
 }
 
 const prodUpgradeCounts = [1, 5, 10, 25, 50, 75, 100];
diff --git a/gorge.js b/gorge.js
index b6981b0..4d95b37 100644
--- a/gorge.js
+++ b/gorge.js
@@ -13,6 +13,7 @@ const resources = {};
 let updateRate = 30;
 
 const currentProductivity = {};
+
 let clickBonus = 0;
 let clickVictim = "micro";
 
@@ -66,7 +67,10 @@ function addPowerup(powerup) {
   updateAll();
 }
 
-function applyGlobalProdBonuses(productivity) {
+function getGlobalProdBonus() {
+
+  let productivity = 1;
+
   for (let effect of effects["prod-all"]) {
 
     if (ownedUpgrades[effect.parent]) {
@@ -78,10 +82,10 @@ function applyGlobalProdBonuses(productivity) {
 }
 
 function calculateProductivity() {
-  let productivity = 0;
+  let productivity = makeCost();
 
   for (const [key, value] of Object.entries(belongings)) {
-    productivity += productivityOf(key);
+    productivity = addCost(productivity, productivityOf(key));
   }
 
   return productivity;
@@ -110,27 +114,42 @@ function productivityMultiplierOf(type) {
 }
 
 function productivityOf(type) {
-  let baseProd = buildings[type].prod;
+  let baseProd = makeCost(buildings[type].prod);
 
-  let prod = baseProd * productivityMultiplierOf(type);
+  baseProd.food *= productivityMultiplierOf(type);
 
-  prod = applyGlobalProdBonuses(prod);
+  baseProd.food *= getGlobalProdBonus();
+
+  baseProd.food *= belongings[type].count;
+
+  return baseProd;
+}
 
-  return prod * belongings[type].count;
+function makeCost(source) {
+  const empty = mapObject(resourceTypes, () => 0);
+  Object.preventExtensions(empty);
+  return {...empty, ...source};
+}
+
+function addCost(cost1, cost2) {
+  return Object.keys(resourceTypes).reduce((o, k) => ({ ...o, [k]: cost1[k] + cost2[k]}), {});
+}
+
+function scaleCost(cost, scale) {
+  return Object.keys(resourceTypes).reduce((o, k) => ({ ...o, [k]: cost[k] * scale}), {});
 }
 
 function costOfBuilding(type, count = 1) {
-  let total = 0;
+  let total = makeCost();
 
   while (count > 0) {
-    let baseCost = buildings[type].cost;
-    let countCost = baseCost * Math.pow(1.15, belongings[type].count + count - 1);
-    total += countCost;
+    let baseCost = makeCost(buildings[type].cost);
+    baseCost.food *= Math.pow(1.15, belongings[type].count + count - 1);
+    total = addCost(total, baseCost);
     count--;
   }
 
-
-  return Math.round(total);
+  return mapObject(total, round);
 }
 
 function buildingCount() {
@@ -148,9 +167,9 @@ function buyBuilding(type, e) {
 
   let cost = costOfBuilding(type, count);
 
-  if (resources.food >= cost) {
+  if (canAfford(cost)) {
+    spend(cost);
     belongings[type].count += count;
-    resources.food -= cost;
   }
 
   updateProductivity();
@@ -181,7 +200,7 @@ function updateDisplay() {
 }
 
 function updateProductivity() {
-  currentProductivity["food"] = calculateProductivity();
+  Object.assign(currentProductivity, calculateProductivity());
 
   activePowerups.forEach(entry => {
     const powerup = entry.powerup;
@@ -193,11 +212,7 @@ function updateProductivity() {
       belongings: belongings
     };
 
-    console.log(currentProductivity);
-
     powerup.effect(state);
-
-    console.log(currentProductivity);
   })
 }
 
@@ -233,7 +248,9 @@ function displayBuildings() {
   for (const [key, value] of Object.entries(belongings)) {
 
     if (!belongings[key].visible) {
-      if (resources.food * 10 >= costOfBuilding(key)) {
+      if (resources.food * 10 >= costOfBuilding(key).food) {
+        unlockBuilding(key);
+      } if (belongings[key].count > 0) {
         unlockBuilding(key);
       } else {
         continue;
@@ -247,15 +264,17 @@ function displayBuildings() {
     let name = document.querySelector("#building-" + key + " > .building-button-name");
     let cost = document.querySelector("#building-" + key + " > .building-button-cost");
 
+    const buildingCost = costOfBuilding(key, count);
+
     name.innerText = value.count + " " + (value.count == 1 ? buildings[key].name : buildings[key].plural);
-    cost.innerText = render(costOfBuilding(key, count)) + " food";
+    cost.innerText = render(buildingCost.food) + " food";
 
-    if (costOfBuilding(key, count) > resources.food) {
-      button.classList.add("building-button-disabled");
-      cost.classList.add("building-button-cost-invalid");
-    } else {
+    if (canAfford(buildingCost)) {
       button.classList.remove("building-button-disabled");
       cost.classList.add("building-button-cost-valid");
+    } else {
+      button.classList.add("building-button-disabled");
+      cost.classList.add("building-button-cost-invalid");
     }
   }
 }
@@ -375,7 +394,7 @@ function buyUpgrade(id, e) {
 }
 
 function eatPrey() {
-  const add = buildings[clickVictim]["prod"] * 10 * productivityMultiplierOf(clickVictim) + clickBonus;
+  const add = buildings[clickVictim]["prod"].food * 10 * productivityMultiplierOf(clickVictim) + clickBonus;
   resources.food += add;
   return add;
 }
@@ -938,7 +957,7 @@ function buildingTooltip(id, event) {
 
   fillTooltip("building", "name", (count != 1 ? count + "x " : "") + buildings[id].name);
   fillTooltip("building", "desc", buildings[id].desc);
-  fillTooltip("building", "cost", render(costOfBuilding(id, count)) + " food");
+  fillTooltip("building", "cost", render(costOfBuilding(id, count).food) + " food");
   fillTooltip("building", "prod", prodSummary(id));
 
   let xPos = tooltip.parentElement.getBoundingClientRect().x - 450;
diff --git a/numbers.js b/numbers.js
index 35a8caf..53ddf83 100644
--- a/numbers.js
+++ b/numbers.js
@@ -3,6 +3,9 @@ function render(val, places = 1, smallPlaces = 0) {
 }
 
 function numberText(val, places = 1, smallPlaces = 0) {
+  if (isNaN(val)) {
+    throw new RangeError("Invalid number: " + val);
+  }
   if (val < 1000) {
     return round(val, smallPlaces);
   }
diff --git a/util.js b/util.js
index fe4e471..c9b90aa 100644
--- a/util.js
+++ b/util.js
@@ -18,3 +18,24 @@ function removeChildren(element) {
 function round(val, places = 0) {
   return Math.round(val * Math.pow(10, places)) / Math.pow(10, places);
 }
+
+function mapObject(obj, func) {
+  return Object.keys(obj).reduce((o, k) => ({ ...o, [k]: func(obj[k])}), {});
+}
+
+function deepFreeze(object) {
+
+  // Retrieve the property names defined on object
+  var propNames = Object.getOwnPropertyNames(object);
+
+  // Freeze properties before freezing self
+  
+  for (let name of propNames) {
+    let value = object[name];
+
+    object[name] = value && typeof value === "object" ? 
+      deepFreeze(value) : value;
+  }
+
+  return Object.freeze(object);
+}